Chicago mobster Frank Calabrese Sr., a known hit man who strangled victims and slit throats, died earlier this week in a federal prison at the age of 75.
Calabrese passed away Tuesday at the Butner Federal Medical Center, said Ed Ross, a spokesman for the North Carolina Federal Bureau of Prisons.
Ross had no information on the cause of death, though Calabrese claimed in 2009 to be suffering from a host of ailments, including an enlarged heart.
"It's very emotional right now because there were two sides to my dad, and I miss the good side," son Frank Calabrese Jr. told the Chicago Sun-Times.
The younger Calabrese isn't kidding about his mixed emotions; he actually helped put his father away by secretly recording him boasting about mob killings.
Calabrese was among five men convicted in September 2007 at the Family Secrets trial, part of the government's years-long effort to derail the "Chicago Outfit."
The investigation also was aimed at clearing 18 unsolved murders dating back to the '70s. Calabrese was blamed for many of them and sentenced to life in prison.
At his trial, Frank's brother testified that Calabrese preferred to strangle victims with a rope and then slash their throats to make sure they were dead.
None of the defendants in the Family Secrets trial was charged with murder.
They were convicted of racketeering, but the jury held Calabrese and two others responsible for killings designed to silence witnesses and carry out vengeance.
Calabrese laughed during some of the trial's most grisly testimony. Frank Calabrese Jr. admits it's been hard to come to grips with this violent history.
"I believe he was taken on Christmas Day for a reason," he said. "I hope he made peace. I hope he's up above looking down on us ... He's not suffering anymore."
"The people on the street aren't suffering anymore."