At the time, it was said that Cali and others allegedly arranged, through force and threat of force, to receive cash payments from someone who had worked on the project.
Multiple press accounts since 2015 said Cali had ascended to the top spot in the gang, although he never faced a criminal charge saying so.
But Gravano would eventually testify against Gotti, leading to Gotti's 1992 conviction in five murders - one of several major convictions that thinned the Mafia ranks in the 1980s and '90s.
Another law enforcement official confirmed to the outlet that the victim was a high-ranking member of the Gambino organized crime family and was believed to be the acting boss.
The Gambino family had previously gained a high profile under the leadership of the late John Gotti - who orchestrated the last public killing of a Gambino crime boss in 1985, when Paul Castellano was gunned down outside of Sparks Steak House in Manhattan. Members of Gotti's own family allegedly tried to step into the leadership shoes, but were unsuccessful. After Gotti went to prison, Cali eventually took over the organization.More news: This Is The Schedule For Liverpool After Champions League Quarter-Final Qualification
More news: Game of Thrones making: Here’s how the White Walkers came to life
More news: Kate Middleton Has a Blast With Babies While Talking Parenting
His widow is the niece of Gambino capo John Gambino. Capeci said the killing "doesn't have the feel" of a Mafia-sanctioned hit.
"It takes a certain type of evil to murder a friend in their own home, and then console the grieving relatives", said Federal Bureau of Investigation assistant director in charge William Sweeney.
Castellano's death led to the rise of John "Dapper Don" Gotti, who then took over as Gambino family boss, running criminal enterprises ranging from gambling to money laundering to prostitution.
Business Insider reported in 2013 that Cali had reportedly turned down an offer to head the crime family.
Last October, 71-year-old Sylvester Zottola, a reputed associate of the Bonanno organisation, was shot dead at a takeaway restaurant in the Bronx, New York. He was sentenced to 16 months behind bars and was released in 2009. At a 2008 bail, a prosecutor said Cali was seen "as a man of influence and power by organised crime members in Italy".