Dr. Bundesen immediately established a coroner's jury made up of seven prominent Chicago citizens. The jury went to the warehouse shortly after the killings to view the scene first-hand. The foreman of the coroner's jury, Bert A. Massee, knew of Goddard and his firearms work. A day or so after the crime, he phoned Goddard at the Bureau of Forensic Ballistics and asked him to drop everything and come to Chicago. Goddard traveled to Chicago the following day and was given the largest number of firearms exhibits he had ever received from any single case.3
Seventy empty 45-caliber cartridge shells had been gathered from the warehouse floor, all of the same make. By examining the shell casings, Goddard determined that they had been fired from an automatic weapon. Goddard knew that there were only two automatic guns made in the United States that fired .45-caliber ammunition. One was the 45 Colt automatic pistol, and the other the Thompson sub-machine gun, also manufactured by the Colt Company.4 By examining the marks made on the shells by the breech bolt, Goddard knew that the shells had been fired in a Thompson sub-machine gun. By differentiating two distinct sets of ejector marks on the cartridge case, Goddard determined that two weapons had fired the seventy shells. Fifty cartridges had been fired from one Thompson and twenty from the other. From this Goddard concluded that one sub-machine gun had been loaded with a twenty-shot clip and the other a fifty-shot drum.
The police had picked up fourteen bullets from the garage floor. These projectiles had either missed or passed through their targets. All but two were deformed from impact. The rifling marks on the slugs indicated they had been fired through a barrel with six grooves twisting to the right. This was characteristic of a Thompson sub-machine gun. The bullets all contained two manufacturer's marks made by the U.S. Cartridge Company. Goddard learned that ammunition marks like this had only been produced during the period July, 1927 to July, 1928.5
Goddard also examined forty-seven bullet fragments that had been collected from the warehouse floor. Many of these pieces were large enough to contain the imprints of the U.S. Cartridge Company. Most of the fragments showed rifling marks that bore grooves characteristic of the Thompson type of rifling. Two empty twelve gauge shot-gun shells had also been found. They contained traces of smokeless powder and had been loaded with buck-shot. The firing pin imprints on the shot gun casings indicated they had been fired from the same weapon.
Thirty-nine bullets and bullet fragments had been removed from the seven dead men. The body of Adam Heyer, the accountant, yielded fourteen. The bodies of James Clark and Frank Gusenberg produced seven each, and six had been extracted from Alexander Weinshenk. The remaining five bullets were shared by the other three victims. Reinhardt Schwemmer, the hapless eye doctor, was the one who had been shot-gunned. Seven buck-shot projectiles had been removed from his body.
As Goddard labored over his firearms evidence, the shocked citizens of Chicago grappled for a solution. A reward of $100,000 was offered. The money was collected from government institutions, business groups, and the general public. Meanwhile, wild charges were being thrown about. The assistant administrator of the federal prohibition force in Chicago publicly theorized that the killers were corrupt Chicago policemen who had been feuding with Moran.6 The next day the prohibition administrator retracted his statement, claiming that he had been misquoted. The federal government transferred the official out of Chicago, but the suspicion lingered.
The magnitude of the crime put the Chicago police department under tremendous pressure. The fact that many people believed that policemen had been involved created an additional incentive to solve the case. Because of this suspicion, coroner Bundesen asked Goddard to test several shot-guns and Thompson sub-machine guns in the hands of the police in Chicago and its suburbs. Goddard would also examine the guns possessed by the Cook County Police Force. Goddard test-fired eight Thompsons and sixteen shot-guns. By comparing the police bullets and cartridge cases with the evidence found in the warehouse, Goddard concluded that none of these weapons had been used in the crime. Goddard's findings helped lift some of the suspicion off the Chicago police.
After Goddard had completed his initial firearms work, he returned to the Bureau of Forensic Ballistics in New York City. Over the next several months Coroner Bundesen would send Goddard dozens of Thompson sub-machine guns for testing. None of them turned out to be a murder weapon.
The day after the killings, Bugs Moran read in the newspapers that the police wanted to question him about the massacre. Moran presented himself to the police, and when investigators asked him about his theory of the murders, he stated, “Only Capone kills like that.”
When all this was going on, Capone was in Florida relaxing at this Miami villa. The authorities in Florida had given him the perfect alibi, on the morning of February 14, Capone was in the office of the Dade County solicitor being questioned about his criminal activities in the Miami area.
The first arrest in the case came on February 27, 1929. The arrestee was Jack McGurn (real name, James DeMora), Capone's favorite executioner, a hood credited with twenty-two murders.7 A witness who had passed by the warehouse on the fatal morning had heard one of the killers say, “Come on, Mac.” This witness identified a photograph of McGurn as one of the executioners. Following his arrest, McGurn immediately posted the $50,000 bail and was out on the street. It was believed that McGurn had masterminded the massacre.
3. About a year after the St. Valentines Day Massacre, Goddard recorded the details of his work on the case in the following article: Goddard, Calvin, “The Valentine’s Day massacre: A Study in Ammunition Tracing,” American Journal of Police Science, 1:1 (1930), pp 60-78.
4. The Thompson sub-machine gun was invented in 1920 by General John Thompson. The Colt Co. started selling it in 1921. It was the first weapon of its kind. It weighed 9 pounds and fired standard .45-caliber bullets. The gun had a range of 6,000 yards and could fire 1,500 rounds a minute. The early model cost $175.00. The army couldn't afford the gun because it fired too many bullets. Bootleggers had the money and found it quite useful. The Thompson was first used by gangsters in Chicago in 1925. J. Edgar Hoover was fascinated by the weapon and adopted it as a standard FBI weapon in the mid 1930's. It wasn't until the late twenties that laws were passed making the possession of the weapon illegal. By then, gangsters were paying five thousand dollars for the gun. See: Helmer, William J., The Gun that Made the Twenties Roar, London: Collier-Mcmillan Co., 1969.
5. All of the bullets fired at the warehouse were stamped with a small letter “s” and imprinted with an encircling ring. This told Goddard that the ammunition was of the U.S. Cartridge brand and made during that one year period.
6. A month before the massacre, 500 cases of liquor destined for the Moran warehouse had been seized by hijackers. Federal prohibition agents believed that crooked police were responsible for the heist. It was theorized that Moran had found out about this and had threatened to expose the policeman. In response, the police had plotted to kill Moran before they were either killed or disgraced. The prohibition official making these charges was Frederick D. Silloway.
7. For more on McGurn and his involvement in the St. Valentine’s Day Massacre, see: Halper, Albert (Ed.), The Chicago Crime Book, Cleveland: The World Publishing Co., 1967.