NEW YORK – The mystery began with a heart attack, a man with a past, and a bag of money that federal authorities now want to keep.

In August, a retired Teamster from Boston stepped off an Amtrak train in New York City and collapsed on the platform at Pennsylvania Station. As medics tried to revive him, police searched his backpack for identification. Inside, they found $179,980 in cash, bundled with rubber bands and tucked inside two plastic bags.

The dead man, William P. Coyman, 75, a lifelong resident of Boston’s Charlestown section, had a criminal history dating to 1955. His record included prison time in New Hampshire after he was caught with a pile of cocaine and $20,000 that had just been stolen from a department store.

Coyman’s old union, International Brotherhood of Teamsters Local 25, was notorious for its organized crime ties in the 1990s.

Years ago, Coyman’s name was mentioned in news articles about allegations that union officials were shaking down Hollywood film crews and forcing producers to give cushy film set jobs to gangland hoodlums. He’d worked as a driver on some of the films in question.

Police brought in a drug-sniffing dog, which indicated traces of narcotics in both Coyman’s backpack and briefcase, according to a court filing. Investigators contacted one of Coyman’s relatives, who said he had been working as a courier for a company called 180 Entertainment and was supposed to have been delivering cash from Boston to Philadelphia when he died.

Agents looked into the company and found that its registered headquarters was a small house in a blue-collar section of Philadelphia, with personal watercraft and two luxury cars parked in the driveway.

All this made the Drug Enforcement Administration suspicious. In February, federal prosecutors in New York asked a judge for permission to keep the cash as the suspected proceeds of drug dealing.

A lawyer from Providence, R.I., has filed court papers claiming the cash on behalf of 180 Entertainment. In the filings, Steven D. DiLibero identified his client as a man named Joseph Burke.

Court records show that Burke, another longtime Charlestown resident, was sent to prison in 1988 for a string of six bank robberies in Florida. At the time, he told FBI agents he had been involved in as many as 18 heists of banks and armored cars, in several states, before being captured in Minnesota.

Prison didn’t rob him of his criminal impulses. While still incarcerated, in 1994, Burke was caught in an FBI sting conspiring to distribute 5 kilograms of cocaine in Charlestown with the help of some associates. He had more time tacked on to his sentence and was finally released on a combination of probation and parole in October 2010.

On April 20, Burke was arrested on an alleged probation violation. Since his release from prison, he had failed a drug test and also had been accused of leaving the country without permission, according to lawyers and a judge at an initial hearing on the matter.

Real estate documents show that the Philadelphia house listed in some records as the headquarters of 180 Entertainment is owned by Anthony Fedele, a former business partner of the late Philadelphia music producer Stephen Epstein.

Before his death, Epstein was known for being a close friend and occasional business partner of Joseph “Skinny Joey” Merlino, the onetime boss of the Philadelphia mafia.

The courts have yet to rule on whether the DEA will get to keep the money.