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 the stuff that "Law & Order" episodes are made of: $179,980 in cash, bundled with rubber bands and tucked inside two plastic bags.

That raised some eyebrows. So did the dead man's background.

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 very suspicious.

In February, federal prosecutors in New York asked a judge for permission to keep the cash as the suspected proceeds of drug dealing.

Reached by the AP in California, Coyman's son, also named William, declined to speak about the situation, other than to say that the money didn't belong to the family.

"The people connected to that money are probably not good people," he said. "My dad was a great man. But clearly he had a colorful history. ... As a kid growing up, my father was in the newspaper and it was embarrassing. It has been embarrassing my whole life."

Friends and relatives who posted remembrances of Coyman on websites after his death recalled the brighter side of his life, including a fondness for Irish song, loyalty to family and an affinity for the local horse track.

A lawyer from Providence, R.I., has filed court papers claiming the cash on behalf of 180 Entertainment. In the filings, the attorney, Steven D. DiLibero, identified his client as a man named Joseph Burke but didn't explain the company's business or say where the money was headed.

Court records obtained by The Associated Press show that Burke is another longtime Charlestown resident with a colorful past.

In 1988, he was sent to prison 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.

Contacted by The AP, DiLibero said he wouldn't talk about Burke or give any information about the mysterious $180,000.

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 remarks made by lawyers and a judge at an initial hearing on the matter.

Prosecutors involved in Burke's cases in New York and Boston didn't return phone calls. A spokeswoman for the DEA declined to comment.

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.

Coincidentally, A&E announced in March that it had teamed up with Boston-born actor Mark Wahlberg to make an unscripted docudrama about Coyman's old union, Teamsters Local 25. The union says it cleaned up its act years ago after top officials were convicted in a series of federal racketeering investigations.