Eventually Reles partnered with a mixed group of Jewish and Italian gangsters based in Brownsville and neighboring Ocean Hill sections of Brooklyn. These men who included notorious killers Harry "Pittsburgh Phil" Strauss, Harry "Happy" Maione, Frank "The Dasher" Abbandando, Louis Capone, Allie "Tic Toc" Tannenbaum and Martin "Buggsy" Goldstein, would eventually form the core of the group dubbed Murder, Inc.
Throughout the 1930s, Reles and his cohorts were able to eliminate local competition through assassination. These included the murders of the Shapiro brothers, who until their demise ran most of the Brooklyn bootlegging, slot and vending machine rackets. One by one, each Shapiro brother was eliminated by execution. Meyer, the eldest was found dead under the sands of Canarsie beach, in a sack in which he had been buried alive. Others who met their demise were the Amberg brothers, who were hoodlums based in Williamsburg. Soon Reles and crew dominated the Brooklyn rackets.
After attracting the attention of big time gangsters like Louis "Lepke" Buchalter and Albert "The Lord High Executioner" Anastasia, Reles and his troop became the execution arm of what was known as The Syndicate, whose membership included at various times Lucky Luciano, Meyer Lansky, Benjamin "Bugsy" Siegel, Dutch Schultz and Joe Adonis. The group would be called into action after The Syndicate would determine (often in mock trials with the gangsters acting as prosecutor, defense attorney and judge) that someone needed to be eliminated for breaking underworld laws.
Reles and his partners excelled at this particular vocation. Dispatched to various cities and towns throughout the United States, ice picks, ropes, guns, hatchets and hands were all employed by the men to achieve their goals. Sometimes they worked in small teams and other times they worked solo, but they were extremely well organized and meticulous in their planning, using crash cars to stop pursuing police officers and never leaving witnesses behind.
Soon the group expanded to include Lepke's personal killers Charlie Workman and Emmanuel "Mendy" Weiss. One of the group's most infamous hits was of Dutch Schultz, who was killed by order of the syndicate and for which Workman was convicted of murder. They also worked with Bugsy Siegel on at least one assassination committed in Los Angeles.
It is believed that the group was responsible for at least 1,000 murders, including one war of extermination waged on behalf of Buchalter who was attempting to eliminate any witnesses who could possibly testify against him. During this particular 1939 campaign at least 12 low level gangsters were eliminated.
While Reles was able to elude conviction on countless criminal charges, including six homicide charges, he did serve several prison terms prior to 1940 including one in the 1930s for assaulting an African American parking lot attendant who had protested Reles's insistent honking.
In 1940 after a minor associate turned informant things quickly began to unravel for Reles and the rest of the troop. Seeing the writing on the wall, Reles turned informant and began to reveal the inner workings of Murder, Inc to Brooklyn Assistant District Attorney Burton Kaplan. With his testimony and amazing recollection for details the police were able to close the book on 85 murders in Brooklyn alone. He also testified at trials in Los Angeles and Newark.
Along with members of his own gang, Reles implicated Buchalter and Albert Anastasia in countless homicides and detailed the inner workings and structure of the murder organization.
On November 12, 1941, the night before he was to begin his testimony against Anastasia, Reles was found dead on a low lying roof outside the window of the Half Moon Hotel in Coney Island where he had been under 24 police protection since he had become an informant. Bed sheets tied together in a crude knot were found hanging from the window attached to a wire connected to a radiator.
There are many who believe Reles was thrown from the window especially in light of the sloppy workmanship of the knots considering Reles a professional murderer certainly had advanced knowledge of knots.
Reles's death quickly earned fame in popular culture after someone near his body was said to utter the words "the canary could sing, but he couldn't fly."
Eventually most of the crew, including Lepke Buchalter, Mendy Weiss, Happy Maione, Pittsburgh Phil Strauss, Louis Capone, Dasher Abbandando and Buggsy Goldstein, ended up convicted on various murder charges and spent their last earthly moments in the Sing Sing electric chair. Albert Anastasia's death came in a chair as well, except his was in a barber's chair at NYC's Park Sheraton Hotel at the hands of assassins on October 25, 1957.