The Disturbing Story Of The Heart Attack Gun Invented By The CIA During The Cold War

Published January 31, 2022

The heart attack gun fired a dart made of frozen shellfish toxin that would enter the target's bloodstream and kill them in mere minutes without leaving a trace.

Heart Attack Gun

Associated PressSenator Frank Church (left) holds aloft the “heart attack gun” during a public hearing.

In 1975, more than 30 years of almost unrestricted CIA activity came grinding to a halt before Senator Frank Church on Capitol Hill. After the shocking revelations of the Watergate scandal, the American public had suddenly gained an intense interest in the activities of their intelligence agencies. Unable to resist the growing disquiet any longer, Congress was forced to peer into dark corners of the Cold War — and some of them held bizarre secrets.

What they found was the stuff of paranoid thrillers and hair-raising spy fiction alike. Aside from plans to assassinate national leaders from across the globe and extensive spying on American citizens, investigators came across the heart attack gun, a macabre weapon which could cause death in minutes without leaving a trace.

This is the story of what may be one of the Central Intelligence Agency’s most chilling gadgets.

The ‘Heart Attack Gun’ Is Born Of Shellfish Toxin

Mary Embree Former Cia Agent

YouTubeMary Embree was the researcher tasked with finding an “untraceable” poison for a range of uses, including the heart attack gun.

The roots of the heart attack gun lay in the work of one Mary Embree. Going to work for the CIA as an 18-year old high school graduate, Embree was a secretary in a division tasked with devising hidden microphones and other audio surveillance equipment, before being promoted to the Office of Technical Services. Eventually, she was ordered to find an undetectable poison. Her research led her to conclude that shellfish toxins were the ideal choice.

Unbeknownst to her, Embree had been made a part of Project MKNAOMI, a highly secretive program dedicated to crafting biological weapons for the United States’ Cold War arsenal and successor to the far more infamous Project MKULTRA. But while other MKNAOMI projects were dedicated to poisoning crops and livestock, Embree’s findings were destined to form the basis of the brass ring of black ops: killing a human being — and getting away with it.

The Development Of The Heart Attack Gun

Fidel Castro 1959

Library of CongressThe heart attack gun may have been intended for use on Cuban leader Fidel Castro, himself a survivor of numerous assassination attempts.

Work began in a laboratory in Fort Detrick, an Army base dedicated to biological warfare research since World War II. There, researchers under Dr. Nathan Gordon, a CIA chemist, mixed shellfish toxin with water and froze the mixture into a small pellet or dart. The finished projectile would be fired from a modified Colt M1911 pistol equipped with an electrical firing mechanism. It had an effective range of 100 meters and was virtually noiseless when fired.

When fired into a target, the frozen dart would immediately melt and release its poisonous payload into the victim’s bloodstream. Shellfish toxins, which are known to completely shut down the cardiovascular system in concentrated doses, would spread to the victim’s heart, mimicking a heart attack and causing death within minutes.

All that would be left behind was a tiny red dot where the dart entered the body, undetectable to those who didn’t know to look for it. As the target lay dying, the assassin could escape without notice.

The Heart Attack Gun Is Revealed

Sidney Gottlieb 1977

Wikimedia CommonsDr. SIdney Gottlieb, head of the CIA’s Project MKULTRA, directed Dr. Nathan Gordon to turn over the shellfish toxin stockpile to Army researchers, but was ignored.

The heart attack gun may have seemed like an outlandish idea from a spy novel, but the CIA had reason to believe it would work perfectly. After all, KGB hitman Bohdan Stashynsky had used a similar, cruder weapon with success not once, but twice, in 1957 and again in 1959. Years after leaving the CIA, Embree claimed that the modified pistol, known as a “nondiscernible microbionoculator,” had been tested on animals and prisoners to great effect.

Patrice Lumumba Arrested

Bettmann/Getty ImagesAmong other things, the Church Committee investigated possible American involvement in the deaths or attempted killings of leaders like Patrice Lumumba of the Democratic Republic of the Congo.

Along with a number of other MKNAOMI creations, the heart attack gun might never have been detected if not for a growing awareness of illegal activities carried out by the United States intelligence community. When a New York Times article revealed a series of reports detailing illegal operations dubbed “the family jewels,” the Senate convened a select committee chaired by Idaho Senator Frank Church to investigate the depth of criminal intelligence actions in 1975.

The Church Committee soon became aware that former President Richard Nixon had shut down MKNAOMI in 1970. They also learned that Dr. Gordon, against the orders of Dr. Sidney Gottlieb, the elusive head of Project MKULTRA, had secreted 5.9 grams of shellfish toxin — nearly a third of all shellfish toxin ever produced at the time — and vials of toxin derived from cobra venom in a Washington, D.C. laboratory. The committee also investigated allegedly sanctioned assassination plans targeting leaders such as Cuba’s Fidel Castro, Patrice Lumumba of the Congo, and Rafael Trujillo, dictator of the Dominican Republic.

The End Of CIA Wetwork

Ford Administration Meeting

Gerald R. Ford Presidential Library and MuseumWilliam Colby, far left, was critical of the Church Committee, arguing that it had “placed American intelligence in danger.”

In a highly publicized hearing, CIA Director William Colby himself was called to testify before the committee. He brought with him the heart attack gun itself, allowing committee members to handle the weapon as they queried him about its development, nature, and use. What became of the gun after its single public viewing is unknown.

Furthermore, whether the weapon was ever used is also unknown. The toxin may have been put to further use as a suicide pill for American operatives or as a powerful sedative and was set aside for one operation, but as Colby claimed, “we are aware that that operation was not in fact completed.”

Partially due to the Church Committee’s findings, in 1976 President Gerald Ford signed an executive order forbidding any employee of the government to “engage in, or conspire to engage in, political assassination.” If ever there was an era of the heart attack gun, it came to a close when that order was signed, bringing to an end the CIA’s most notoriously secretive and violent years.


After learning about the heart attack gun, find out more about the Umbrella Man, the shadowy figure who may hold the key to the JFK assassination. Then, read about Santo Trafficante, Jr., the Florida mob boss whose work for the CIA included the most infamous attempt on Fidel Castro’s life.

Morgan Dunn
Morgan Dunn is a freelance writer who holds a bachelor’s degree in fine art and art history from Goldsmiths, University of London. His areas of interest include the Soviet Union, China, and the far-reaching effects of colonialism.