Vito Rizzuto, Canadian...

...mafia boss, died at age 67. I'd never heard of him, but this is from his obit in the Times:

But Mr. Rizzuto’s luck ran out in 2004, when he was arrested in Montreal on racketeering charges related to a gangland shooting in Brooklyn that inspired a bloody scene in the 1997 film “Donnie Brasco,” starring Al Pacino and Johnny Depp.

In the shooting, on May 5, 1981, Mr. Rizzuto and three other men burst from the closet of a Brooklyn social club and shot three Bonanno captains who had been challenging the family’s leadership, the authorities said. The shooters wore ski masks to make the killing look like a robbery, but the authorities said it had been ordered by Joseph Massino, then a senior Bonanno captain.

I've never seen Donnie Brasco, but I assume that's the scene above. It's not often that you see people die slowly in movies or cry out in pain, but I'll bet that's how it happens in real life.