Step 1 : Introduction to the question "Which mobster's testimony sent John Gotti to prison?"
Salvatore "Sammy the Bull" Gravano is a former underboss of the Gambino crime family. He is known as the man who helped bring down John Gotti, the family's boss, by agreeing to testify against him in a deal in which he confessed to involvement in 19 murders. On this day in 1992, Mafia boss John Gotti was sentenced to life in prison after being found guilty on 14 accounts of conspiracy to commit murder and racketeering. As part of Gravano's cooperation agreement, he received a reduced sentence and entered the Witness Protection Program.
