Investigation begins Within hours of the shooting, Chicago's district police, the city's detective bureau, the
Illinois Attorney General's office, and the
coroner's office under
Herman Bundesen all opened separate investigations, which operated largely independently from one another. The situation was confused by an announcement, from the Chicago deputy Prohibition administrator Major Frederick D. Silloway, that the police had undertaken the killings. Although he retracted his statement later that day, several newspapers carried headlines that stated the police was involved. The day after the massacre the coroner ordered a reenactment, which was held at the garage. They kept in line with the known events as far as possible, including having Highball the dog present. Instead of a
coroner's jury, Bundesen assembled a panel of unimpeachable Chicagoans to assist, headed up by Burt Massee, the president of the
Colgate Palmolive Peet Company. Plainclothes police and one of the reporters present played the roles of the victims; other police lined up as the gunmen, each holding a shotgun. Bundesen formally opened his inquest the same day. Massee contacted
Calvin Goddard, a pioneer in
forensic ballistics, and paid for him to set up a laboratory in Chicago with his team and all his equipment. He soon began examining shell casings and bullets from the scene. He also examined the Thompson machine guns owned by the Chicago police and stated that their weapons had not been used in the shootings. Police began house-to-house questioning of residents and shop-owners. At 2051 North Clark, the
rooming house opposite the garage, they spoke with the proprietress, Minnie Arvidson. She described two men who claimed to be taxi drivers that had taken a room at the front of the house, overlooking the garage. These were later identified as Byron Bolton and James "Jimmy the Swede" Morand (or possibly Jimmy McCrussen), the lookouts. A second landlady, Mrs. Michael Doody of 2119 North Clark, provided details of what turned out to be another possible lookout. He also claimed to be a taxi driver, who would arrive at the house each day at 9:00 am and was joined by two other men at around 9:30 am; they would leave at around 3:30 pm. She was shown photographs of possible suspects and identified
Harry Keywell, a member of the Purple Gang. When he was later questioned, Keywell provided a solid alibi for his activities on the date and time of the shooting. Police also raided many of the city's speakeasies, causing the Chicago Outfit a considerable loss of income. On February 22, 1929, police were called to the scene of a garage fire on Wood Street, where they found a partially disassembled and burnt 1927 Cadillac sedan. Saws, an ax, and an
acetylene torch had been used in dismantling the vehicle. A police siren was lying in the corner, and a burned hat and coat were on the floor. They also found a Thompson drum magazine and a
Luger pistol. Enquiries turned up a nearby doctor's office where a man with burns had asked for treatment; when he was told to wait, he left. The car had been purchased second-hand in Chicago on December 15, 1928, by James Morton of Los Angeles, California, who paid $350 for it. The
Los Angeles Police Department failed to provide any possible leads as to the man's identity. Police established that the garage had been rented by a man calling himself Frank Rogers, who gave his address as 1859 West North Avenue. This was an annex of the Circus Café, which was operated from the neighboring premises by
Claude Maddox, a gangster with ties to Capone. After searching one of Maddox's offices, the police found a connection with activities in St. Louis, Missouri. Their counterparts there told them that criminals had disguised themselves in police uniforms to commit crimes on several occasions. The best-known perpetrator of this was
Fred Burke, a member of the city's
Egan's Rats crime gang. Burke was described as missing a front tooth and had a partner in crime who went by the name of "James Ray", an alias of
Gus Winkler. One of the witnesses who saw the fake police car arrive outside the North Clark Street garage was the chauffeur of Caldwell, President of the
Chicago Board of Education. He had noticed the police driver was missing a front tooth. Egan's Rats left St. Louis in the mid-1920s and became associated with The Purple Gang of Detroit, which had business connections with Capone. Police soon named Burke as a suspect.
Further evidence On February 27, a second vehicle – a 1926
Peerless touring car – was blown up at the junction of 1st Street and Harvard Avenue in Chicago's
Maywood suburb. Again, a police siren was found at the scene with shotgun shells of the same brand used in the massacre, license plates bearing the same prefix as used by the Chicago detective squad and a small notebook belonging to Weinshank, one of the massacre victims. Police considered this second car and the items a plant to disrupt their investigation. Keefe considers the discovery of the second vehicle to give credibility to the possibility of two cars having been used in the massacre. As Capone was in Florida at the time of the shooting, William Russell, Chicago's police commissioner, ordered an investigation of the other members of the Chicago Outfit. On the same day the Peerless was blown up, police arrested
Jack McGurn at Chicago's
Stevens Hotel, where he and his girlfriend were staying under the names Mr. and Mrs. D'Oro. His girlfriend provided his alibi: that they had spent Valentine's Day together in the hotel room. According to Amanda Parr, McGurn's biographer, he was "one of mob history's most prolific and notorious hit men". Others arrested were members of Capone's gang
John Scalise, Albert Anselmi – both of whom had previously been acquitted of murdering a police officer – and Rocco Fanelli, another Outfit gunman. McGurn, Anselmi and Scalise were all charged with the murders, but the charges were dropped because of a lack of evidence. Capone soon heard that Scalise and Anselmi had met with
Joe Aiello, a long-time rival of Capone's with whom he had a feud. Also present was another of Capone's men, Joe Giunta. Capone heard the men were plotting to assassinate him and take over his territory. Furious at being double-crossed, Capone invited the three to a dinner in their honor at The Planation, a Capone-owned
roadhouse. During the evening, Capone used a cut-down baseball bat to murder all three before he and his men shot the corpses. Their bodies were found on May 8. On May 13, Capone attended a meeting of crime lords in
Atlantic City, New Jersey. Many of the leaders were concerned by the publicity caused by the massacre and increased level of official interest in their business. There was also some anger about the deaths of the three Sicilian hitmen, Anselmi, Scalise, and Giunta. The bosses put pressure on Capone to lower his profile by spending a short time in prison. Leaving Atlantic City, Capone and his bodyguard stopped off in Philadelphia, where they were arrested by two police officers whom Capone knew, James Malone and John Creedon. Within sixteen hours he had been charged, appeared in court, found guilty, and sentenced to a year in prison. The massacre case stagnated until December 1929, when Fred Burke, drunk, drove into another car in
St. Joseph, Michigan. Patrolman Charles Skelly intervened; Burke shot him three times and drove off. Skelly died three hours later. Police raided Burke's bungalow and found $310,000 in bonds recently stolen from a
Wisconsin bank, two Thompson submachine guns with nine ammunition drums, six
tear gas bombs, two rifles, a sawed-off shot gun, and an estimated 5,000 rounds of ammunition. The weapons were forensically examined and were identified as those used in the massacre. Police also discovered that one of them had also been used to murder New York mobster
Frankie Yale eighteen months earlier. No further evidence surfaced relating to the massacre. Burke was captured in March 1931. The case against him was strongest in connection to the murder of Skelly, so he was tried in Michigan for that crime and subsequently sentenced to life imprisonment. He died in prison in 1940. On November 17, 1931, Bundesen closed his inquest. He said: "All who were under suspicion are now dead save one, and he [Burke] has received a life penitentiary sentence." In his final report he concluded that "The killings were by persons unknown." ==Subsequent events and other suspects==