JFK Assassination: Second Shooter from the Grassy Knoll
Introduction
The assassination of President John F. Kennedy on 22 November 1963 in Dallas, Texas has generated more conspiracy literature than almost any other event in modern American history. Within that broader landscape, the "second shooter from the grassy knoll" is the most persistently cited specific claim — the hypothesis that a gunman fired from behind a wooden stockade fence atop a grassy rise north of Elm Street in Dealey Plaza, adding a frontal shot to Lee Harvey Oswald's shots from the rear.
This page focuses on the grassy knoll claim specifically, not the broader JFK assassination conspiracy question. The claim has a particular evidentiary history centred on acoustic analysis, witness testimony, and film analysis. That evidence is examined below.
The Physical Setting
Dealey Plaza lies at the western edge of downtown Dallas. The Texas School Book Depository (TSBD), from which Oswald fired, stood at the northwest corner of the plaza. The presidential motorcade turned from Houston Street onto Elm Street and passed below the TSBD. The "grassy knoll" refers to a grassy embankment on the north side of Elm Street, leading up to a low wooden stockade fence near a railroad overpass. A person standing behind that fence would have had a clear line of sight to the motorcade as it passed below.
Witness testimony placed some attention on that area immediately after the shooting. Dallas Police officers ran toward the knoll within seconds. No gunman was found; no physical evidence of a shot from that location was recovered.
The Acoustic Evidence: Dictabelt and the HSCA
The most consequential evidentiary development came with the House Select Committee on Assassinations (HSCA), which reinvestigated the Kennedy assassination from 1976 to 1979.
The HSCA commissioned acoustic experts James Barger (BBN) and Mark Weiss and Ernest Aschkenasy to analyse a Dictabelt recording made by a Dallas Police motorcycle radio that was apparently left in the open-transmit position during the assassination. The analysis identified four impulse patterns that the experts interpreted as gunshots. Crucially, they identified one of these impulses as originating from the grassy knoll direction with a statistical confidence they characterised as 95%.
Based primarily on this acoustic analysis, the HSCA concluded in its 1979 final report that "scientific acoustical evidence establishes, beyond a reasonable doubt, that two gunmen fired at President John F. Kennedy." The HSCA found "probable conspiracy" and recommended a further investigation by the Department of Justice.
The NRC Rebuttal (1982)
The National Research Council (NRC) convened a panel specifically to review the acoustic evidence. The panel, chaired by Norman Ramsey, found that the Dictabelt impulse patterns the HSCA experts identified as gunshots were recorded approximately one minute after the assassination — not during it — and therefore could not be gunshots. The panel concluded that the acoustic evidence did not support the HSCA's findings. This remains the most authoritative scientific assessment of the acoustic evidence.
The FBI Analysis
The FBI also re-examined the acoustic evidence and reached conclusions consistent with the NRC, rejecting the identification of the alleged knoll impulse as a gunshot.
Witness Testimony
Witness accounts from Dealey Plaza are the other main pillar of the grassy knoll claim.
Some witnesses did report believing that shots came from the knoll area. Dallas Police officers ran toward the knoll immediately after the shots. A few witnesses reported smelling gunpowder near the knoll. Jean Hill, one of the closest witnesses on the south side of Elm Street, initially reported hearing shots from the knoll.
However:
- Witness accounts of the direction of gunfire are notoriously unreliable in open urban spaces, where sound reflects and echoes in unpredictable ways.
- Dallas law enforcement officers who immediately searched the area — including the area behind the fence — found no gunman, no spent casings, no physical disruption consistent with a recent firing position.
- Subsequent interviews and accounts by many of the same witnesses have been inconsistent; some later recalled impressions differently.
- The Warren Commission took extensive witness testimony and found it insufficient to establish a second shooter.
The witness evidence is genuinely mixed; it does not rise to the level of establishing the presence of a second shooter.
The Zapruder Film
Abraham Zapruder filmed the motorcade from an elevated position on the north side of Elm Street, producing the most complete visual record of the assassination. The film has been subjected to exhaustive analysis by independent photogrammetrists, forensic pathologists, and film specialists.
Conspiracy proponents have argued that the "back and to the left" movement of Kennedy's head in frame 313 (the headshot) indicates a shot from the front (the knoll) rather than the rear (the TSBD). The forensic response — accepted by most ballistics and pathology specialists — is that the movement pattern is consistent with a neurological and muscular response to a shot from behind: the jet effect and neuromuscular spasm can produce forward-then-backward movement after a rear shot. Additionally, earlier frames show Kennedy's body already moving forward before the backward motion.
No independent photogrammetric analysis has established a visual origin of the headshot from the knoll.
Physical Evidence: What Was Not Found
A second shooter at the grassy knoll would be expected to leave physical evidence. No such evidence has been produced:
- No second bullet or bullet fragments have been identified as originating from the knoll.
- No spent shell casings were found behind the fence or in the knoll area.
- Blood-spatter and wound trajectory evidence from the autopsy is consistent with a rear entry wound. The Warren Commission's pathologists and subsequent independent forensic reviews have generally supported this.
- No credible eyewitness identified an individual crouching or firing behind the fence during the shooting itself.
- No credible physical evidence of a shooter's firing position has been located in the decades since.
NARA Declassifications (2017–2023)
In compliance with the JFK Records Collection Act, the National Archives has released tranches of previously classified documents in 2017, 2018, 2021, 2022, and 2023. None of the released documents have produced documentary evidence establishing a second shooter at the grassy knoll or identifying a shooter by name. Some documents confirmed prior known facts about CIA and FBI equities in the investigation and disclosure decisions. The declassifications have fuelled ongoing interest but not produced the "smoking gun" for any specific sub-theory.
The Warren Commission vs. the HSCA
The evidentiary record leaves two official competing conclusions:
- Warren Commission (1964): Oswald acted alone. No credible evidence of a second shooter.
- HSCA (1979): Probable conspiracy involving at least two gunmen, based on the acoustic evidence.
- NRC (1982): Acoustic evidence rejected; the impulse was recorded after the shooting.
The scientific consensus following the NRC review is that the acoustic evidence that drove the HSCA conclusion is not reliable. The Warren Commission conclusion — one shooter, Oswald — therefore remains the better-supported position on the current evidence, though "better-supported" does not mean fully resolved.
Why the Claim Persists
The grassy knoll claim combines several factors that make conspiracy framings durable:
- The original acoustic analysis appeared to provide scientific validation of the intuition that there was a second shooter.
- The physical setting of Dealey Plaza does look like a natural firing position.
- Some genuine institutional failures — CIA and FBI withheld relevant information for decades — created an environment of justified scepticism about official accounts.
- Kennedy's assassination remains emotionally and culturally significant enough to sustain popular interest in alternative explanations.
None of these factors constitute evidence of a second shooter.
Verdict
Unsubstantiated. The primary evidentiary basis for the grassy knoll claim (the Dictabelt acoustic analysis) was rejected by the NRC and FBI. No physical evidence of a second shooter — no bullet, no casings, no confirmed firing position — has been produced. Witness testimony is mixed and unreliable as to direction of fire. The HSCA's 1979 "probable conspiracy" conclusion rested on the acoustic evidence the NRC subsequently invalidated. The claim is unsubstantiated but, given the passage of time and the partial document record, not fully resolvable.
Evidence Filters12
HSCA 1979 concluded probable conspiracy based on acoustic evidence
SupportingThe House Select Committee on Assassinations, after commissioning acoustic analysis of a Dictabelt police-radio recording, concluded in 1979 that scientific acoustical evidence established beyond a reasonable doubt that two gunmen fired at Kennedy — including one from the grassy knoll direction.
Rebuttal
The NRC (1982) and FBI subsequently reviewed this acoustic evidence and rejected it, finding that the identified impulses were recorded approximately one minute after the assassination and could not be gunshots. The HSCA conclusion therefore rested on evidence that was later invalidated.
Some witnesses reported hearing shots from the knoll area
SupportingWeakSeveral witnesses in Dealey Plaza reported believing shots came from the grassy knoll direction. Dallas Police officers ran toward the knoll immediately after the shots. A small number of witnesses reported smelling gunpowder near the knoll.
Rebuttal
Witness accounts of the direction of gunfire are notoriously unreliable in open urban spaces where sound reflects unpredictably. Officers who ran to the knoll found no gunman and no physical evidence. Subsequent accounts by the same witnesses have been inconsistent.
Grassy knoll provided a clear line of sight to the motorcade
SupportingWeakThe wooden stockade fence at the top of the grassy knoll offered a clear sightline to Elm Street as the presidential motorcade passed. The location would have been physically viable as a firing position.
Rebuttal
A viable physical location is necessary but not sufficient. No physical evidence — no bullet, no casings, no confirmed firing position — was ever recovered from the knoll or behind the fence. Officers searched the area within seconds of the shots.
Zapruder film head-movement cited as evidence of frontal shot
SupportingWeakThe "back and to the left" movement of Kennedy's head in Zapruder frame 313 has been cited as evidence of a shot from the front (the knoll). Oliver Stone's 1991 film dramatised this interpretation and brought it to mass public attention.
Rebuttal
Most forensic pathologists and ballistics specialists interpret the movement as consistent with a rear-entry shot: the jet effect and a neuromuscular spasm can produce forward-then-backward motion after a rear shot. Kennedy's body is already moving forward before the backward motion in earlier frames. No photogrammetric analysis has established a visual origin from the knoll.
NRC (1982) rejected the acoustic evidence entirely
DebunkingStrongThe National Research Council panel chaired by Norman Ramsey reviewed the Dictabelt acoustic evidence and concluded that the impulse patterns identified as gunshots were recorded approximately one minute after the assassination — not during it — and therefore could not be gunshots. This invalidated the primary scientific basis for the HSCA's grassy knoll conclusion.
FBI acoustic analysis also rejected the knoll shot
DebunkingStrongIndependent FBI analysis of the Dictabelt evidence reached conclusions consistent with the NRC, rejecting the identification of the alleged knoll impulse as a gunshot.
No physical evidence of a second shooter found
DebunkingStrongNo second bullet or bullet fragments from the knoll direction have been identified. No spent shell casings were found behind the fence. No blood-spatter or wound trajectory evidence consistent with a frontal shot has been established. Officers searched the knoll area within seconds.
Warren Commission found no credible second-shooter evidence
DebunkingThe Warren Commission (1964), after extensive investigation and witness testimony, concluded that Oswald acted alone from the TSBD and found no credible evidence of a second shooter at the grassy knoll.
Rebuttal
The Warren Commission has itself been criticised for procedural limitations and incomplete information from CIA and FBI. However, its basic conclusion on the physical evidence at the knoll — that no second shooter was found — has not been overturned by subsequent investigations.
NARA declassifications (2017–2023) have not produced knoll evidence
DebunkingThe release of previously classified JFK documents under the JFK Records Collection Act in 2017, 2018, 2021, 2022, and 2023 has not produced documentary evidence establishing a second shooter at the grassy knoll or identifying a shooter by name.
Bugliosi and Posner argue Oswald acted alone after exhaustive review
DebunkingVincent Bugliosi's *Reclaiming History* (2007, 1,600 pages) and Gerald Posner's *Case Closed* (1993) are the two most exhaustive single-shooter analyses. Both conclude that the grassy knoll evidence is insufficient and that Oswald acted alone.
Show 2 more evidence points
Dealey Plaza witness observations — Holland and Bowers
SupportingWeakS. M. Holland and Lee Bowers, positioned on the railroad overpass and in the tower north of the knoll respectively, both gave 1963 Warren Commission depositions describing smoke, movement, or sounds near the stockade fence on the grassy knoll. Their accounts were taken in evidence but were not foregrounded in the Commission's final narrative, and became foundational references in later second-shooter literature.
HSCA 1979 acoustic analysis lent temporary institutional credibility
SupportingWeakThe House Select Committee on Assassinations concluded in 1979 that acoustic evidence from a Dallas Police Department dictabelt recording indicated a probable second shot from the grassy knoll, lending institutional endorsement to the second-shooter hypothesis for over three years until the 1982 NRC panel found a timing error that invalidated the acoustic finding entirely.
Evidence Cited by Believers6
HSCA 1979 concluded probable conspiracy based on acoustic evidence
SupportingThe House Select Committee on Assassinations, after commissioning acoustic analysis of a Dictabelt police-radio recording, concluded in 1979 that scientific acoustical evidence established beyond a reasonable doubt that two gunmen fired at Kennedy — including one from the grassy knoll direction.
Rebuttal
The NRC (1982) and FBI subsequently reviewed this acoustic evidence and rejected it, finding that the identified impulses were recorded approximately one minute after the assassination and could not be gunshots. The HSCA conclusion therefore rested on evidence that was later invalidated.
Some witnesses reported hearing shots from the knoll area
SupportingWeakSeveral witnesses in Dealey Plaza reported believing shots came from the grassy knoll direction. Dallas Police officers ran toward the knoll immediately after the shots. A small number of witnesses reported smelling gunpowder near the knoll.
Rebuttal
Witness accounts of the direction of gunfire are notoriously unreliable in open urban spaces where sound reflects unpredictably. Officers who ran to the knoll found no gunman and no physical evidence. Subsequent accounts by the same witnesses have been inconsistent.
Grassy knoll provided a clear line of sight to the motorcade
SupportingWeakThe wooden stockade fence at the top of the grassy knoll offered a clear sightline to Elm Street as the presidential motorcade passed. The location would have been physically viable as a firing position.
Rebuttal
A viable physical location is necessary but not sufficient. No physical evidence — no bullet, no casings, no confirmed firing position — was ever recovered from the knoll or behind the fence. Officers searched the area within seconds of the shots.
Zapruder film head-movement cited as evidence of frontal shot
SupportingWeakThe "back and to the left" movement of Kennedy's head in Zapruder frame 313 has been cited as evidence of a shot from the front (the knoll). Oliver Stone's 1991 film dramatised this interpretation and brought it to mass public attention.
Rebuttal
Most forensic pathologists and ballistics specialists interpret the movement as consistent with a rear-entry shot: the jet effect and a neuromuscular spasm can produce forward-then-backward motion after a rear shot. Kennedy's body is already moving forward before the backward motion in earlier frames. No photogrammetric analysis has established a visual origin from the knoll.
Dealey Plaza witness observations — Holland and Bowers
SupportingWeakS. M. Holland and Lee Bowers, positioned on the railroad overpass and in the tower north of the knoll respectively, both gave 1963 Warren Commission depositions describing smoke, movement, or sounds near the stockade fence on the grassy knoll. Their accounts were taken in evidence but were not foregrounded in the Commission's final narrative, and became foundational references in later second-shooter literature.
HSCA 1979 acoustic analysis lent temporary institutional credibility
SupportingWeakThe House Select Committee on Assassinations concluded in 1979 that acoustic evidence from a Dallas Police Department dictabelt recording indicated a probable second shot from the grassy knoll, lending institutional endorsement to the second-shooter hypothesis for over three years until the 1982 NRC panel found a timing error that invalidated the acoustic finding entirely.
Counter-Evidence6
NRC (1982) rejected the acoustic evidence entirely
DebunkingStrongThe National Research Council panel chaired by Norman Ramsey reviewed the Dictabelt acoustic evidence and concluded that the impulse patterns identified as gunshots were recorded approximately one minute after the assassination — not during it — and therefore could not be gunshots. This invalidated the primary scientific basis for the HSCA's grassy knoll conclusion.
FBI acoustic analysis also rejected the knoll shot
DebunkingStrongIndependent FBI analysis of the Dictabelt evidence reached conclusions consistent with the NRC, rejecting the identification of the alleged knoll impulse as a gunshot.
No physical evidence of a second shooter found
DebunkingStrongNo second bullet or bullet fragments from the knoll direction have been identified. No spent shell casings were found behind the fence. No blood-spatter or wound trajectory evidence consistent with a frontal shot has been established. Officers searched the knoll area within seconds.
Warren Commission found no credible second-shooter evidence
DebunkingThe Warren Commission (1964), after extensive investigation and witness testimony, concluded that Oswald acted alone from the TSBD and found no credible evidence of a second shooter at the grassy knoll.
Rebuttal
The Warren Commission has itself been criticised for procedural limitations and incomplete information from CIA and FBI. However, its basic conclusion on the physical evidence at the knoll — that no second shooter was found — has not been overturned by subsequent investigations.
NARA declassifications (2017–2023) have not produced knoll evidence
DebunkingThe release of previously classified JFK documents under the JFK Records Collection Act in 2017, 2018, 2021, 2022, and 2023 has not produced documentary evidence establishing a second shooter at the grassy knoll or identifying a shooter by name.
Bugliosi and Posner argue Oswald acted alone after exhaustive review
DebunkingVincent Bugliosi's *Reclaiming History* (2007, 1,600 pages) and Gerald Posner's *Case Closed* (1993) are the two most exhaustive single-shooter analyses. Both conclude that the grassy knoll evidence is insufficient and that Oswald acted alone.
Timeline
Kennedy assassinated in Dealey Plaza; officers run to grassy knoll
President Kennedy is shot in Dallas, Texas. Within seconds of the shots, Dallas Police officers run toward the grassy knoll based partly on witness reactions. No gunman is found; no physical evidence is recovered from the fence area.
Warren Commission concludes Oswald acted alone
The Warren Commission's final report finds no credible evidence of a second shooter at the grassy knoll and concludes that Oswald acted alone from the Texas School Book Depository.
Source →HSCA concludes probable conspiracy based on acoustic evidence
The House Select Committee on Assassinations concludes that scientific acoustical evidence establishes beyond a reasonable doubt that two gunmen fired at Kennedy, including one from the grassy knoll. The committee finds probable conspiracy.
Source →NRC panel rejects HSCA acoustic evidence
The National Research Council panel chaired by Norman Ramsey reviews the Dictabelt acoustic evidence and concludes that the impulse patterns identified as gunshots were recorded approximately one minute after the assassination — not during it — invalidating the primary scientific basis for the HSCA's grassy knoll conclusion.
Source →
Verdict
The grassy knoll second-shooter claim rests primarily on acoustic analysis of a Dictabelt police-radio recording (basis for the HSCA 1979 "probable conspiracy" conclusion). The NRC (1982) and FBI independently rejected the acoustic evidence, finding the identified impulses were recorded after the assassination. No physical evidence of a second shooter (no bullet, no shell casings, no firing-position evidence) has been recovered. Witness testimony is genuinely mixed but insufficient to establish a second shooter. Unsubstantiated but not fully resolvable.