Crime Library: Criminal Minds and Methods

Ballistics: The Science of Guns

The Bullets of Valentine's Day

When smoothbore pistols and muskets were replaced in the late 18th century by rifled weapons, spent bullets acquired a distinct signature. The process of making grooves in rifles for more accurate projectiles meant that they would leave a mark on the softer metal of the bullet as it spun through the barrel. Because of the wearing of the machines that made them, any bullet fired from a specific weapon will bear the same distinct markings. When bullets were then encased in cartridges, even more marks were made, helping investigators make a match between a bullet and a gun.

Book cover: Bodies of Evidence
Book cover: Bo-
dies of Evidence

Firearms evidence identification matching bullets to guns was born in 1835 in England when the unique ridge on a bullet taken from a victim was linked with a bullet mold in the suspect's home, exposing a burglary as a fake. Confronted, the suspect confessed. While that's not a very precise method of matching, it was a start.

The first time an expert proved in court that a specific gun was used for a murder was in America in 1902. Oliver Wendell Holmes, says Brian Innes in Bodies of Evidence, had read a book about firearm identification, so he called a gunsmith to test-fire the alleged murder weapon into a wad of cotton wool. He then used a magnifying lens to match marks on the bullet from the victim to the test-fired bullet, and these he showed to the jury.

St. Valentine's Day Massacre (CHS)
St. Valentine's Day Massacre (CHS)

It was a firearms case, the St. Valentine's Day Massacre on a snow-blown February 14, 1929, that led to the opening of the first independent scientific crime detection laboratory in America. Seven men were waiting that morning around 10:30 a.m. in a red brick warehouse for the S-M-C Cartage Company on Chicago's North Side, at 2122 North Clark Street. Three men wearing police uniforms and two dressed as civilians arrived in a police car and went inside. Witnesses in the neighborhood heard multiple gunshots made by machine guns. Then the police left, and a dog inside left alive the building began to bark and howl. Neighbors checked and found a bloody scene: the seven unarmed men lay on the floor, all shot in the back multiple times. The wall against which they had been lined up for the assassination was a gory mess.

The victims, according to the History Channels' Forensic Firsts, were known associates of mobster George "Bugs" Moran. He pointed the finger at Al Capone, while Capone, down in Florida, pointed it back at him. However, many people thought the police had killed a gang in cold blood, so it was left to firearms comparisons to unearth the true story.

Thomson submachine gun
Thomson submachine gun

The shooters had left behind 70 cartridge casings and the weapons were identified as .45-caliber Thomson submachine guns.

The person who would make all the difference in this case was a cardiologist named Calvin Goddard—the same person who had confirmed the ballistics evidence in the Sacco and Vanzetti case two years earlier. With Charles Waite, who had test-fired the Stielow gun for proof that the immigrant had not committed the double homicide for which he'd been convicted, he began to acquire data from all known gun manufacturers to develop a comprehensive database. Together they catalogued the results of the test fires from each type of gun. At the time, there were 12 known handgun manufacturers, and they started what would become one of the most comprehensive collections of crime-solving information about guns. Waite died in 1925, but Goddard took over the work, and he was responsible, with his scientific procedures, for bringing the science of ballistics into its own.

With the invention of the comparison microscope by Goddard's partner, two objects could be laid side-by-side for high-powered comparative examination using a series of reflective mirrors and lenses. Bullets could be laid out in such a way as to show whether there was a match in the markings that a gun would leave on them after they were fired from that gun. That made for a controlled examination, which was needed as a defensive weapon against the increase in crime during the 1920s.

Thus, when the seven bullet-ridden bodies were found in the Chicago warehouse on St. Valentine's Day in 1929, it was just a matter of finding the murder weapon. Goddard came in from New York as an independent investigator and fired each of the eight machine guns owned by the Chicago police. He then compared the results to evidence collected at the scene. No casings matched, which cleared the police. That meant that someone had impersonated police officers to commit the murders.

Ten months later, the police raided the home of a hit man for Al Capone. They found two machine guns, which they gave to Goddard. He test-fired them and proved they were the weapons used in the massacre. That sent at least one of the killers to prison.

George "Bugs"
Moran (AP)

The infamous incident turned out to have been part of a gang war between Capone and Moran. Evidently the men had been lured there—and Moran was supposed to have been among them—by a call from Detroit indicating that a truck full of hijacked whiskey was coming in. Moran himself was late, and he just missed being victim number eight. In fact, he had spotted the police car outside the warehouse and left.

Goddard's work inspired two businessmen who had been on the coroner's jury to set him up at Northwestern University in Chicago in the first independent crime lab in the country. Ballistics, fingerprinting, blood analysis and trace evidence were brought under one roof and the lab became a prototype. Science and the police were united, and according to Nickell and Fischer, Goddard then advised the FBI in 1932 when they set up a similar criminological laboratory. Their first piece of equipment was a comparison microscope.

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