The former boss of a major New York crime gang has died, after serving 33 of a 139-year prison sentence.

Carmine Persico's lawyer said he died of complications arising from diabetes. He leaves a wife, two children and 15 grandchildren, BBC reports.

The 85-year-old was known as The Snake, a nickname he reportedly hated.

He is thought to have continued running his criminal organisation from behind bars, making his one of the longest-running mob leaderships in history.

Persico was born in Brooklyn in 1933, the son of a law firm stenographer. Before his teens were over, he had been arrested for murder.

A high school dropout, he became the leader of a street gang and was 17 when he was arrested for the fatal beating of another young man in a park fight. The charges were dropped.

He advanced in the Colombo organisation, one of five crime "families" in the Italian-American Mafia in New York at the time, and eventually reached leadership in the 1970s, after internecine strife with other gang leaders.

It was through a landmark 1986 case, led by Rudy Giuliani, later a mayor of New York and presently President Donald Trump's lawyer, that the crime boss was finally put in jail.

Mr Giuliani, who at the time was the US Attorney for Manhattan, also jailed seven others on racketeering charges.

Persico represented himself in court but was found guilty of being the leader of the Colombo family and extorting millions of dollars from unions and construction companies.

"He was the most fascinating figure I encountered in the world of organised crime," a former federal prosecutor told the New York Times.

"Because of his reputation for intelligence and toughness, he was a legend by the age of 17, and later as a mob boss he became a folk hero in certain areas of Brooklyn," Edward A McDonald said.

Persico is reported to have been involved in more than 20 murders, either carrying out the killings himself or by giving the order.

One day in 1961 a police sergeant walked in to a bar to find him and another man strangling someone with a rope. The assault charges were dropped due to lack of testimony - a common theme in attempted prosecutions of Persico.

He was also accused of being involved in loan sharking, assault, burglary, attempted rape, hijacking, possession of an unregistered gun and other charges.

Persico's lawyer, Benson Weintraub, alleged that Persico was not properly cared for while in prison, which contributed to his death.