BOSTON (AP) — Federal prosecutors say a claim by a lawyer for reputed gangster James “Whitey” Bulger that he was never an FBI informant is a tactic to influence jurors in Bulger’s upcoming trial.

Bulger, the former leader of Boston’s notorious Winter Hill Gang, is awaiting trial on a racketeering indictment that charges him with participating in 19 murders.

READ MORE: How Long Should You Wait To Be Boosted After Getting COVID? Dr. Mallika Marshall Answers Your COVID Questions

His lawyer has claimed repeatedly that a former federal prosecutor gave Bulger immunity to commit crimes.

READ MORE: I-Team: Mass General Brigham Nurses Concerned About Limited Supply Of N95 Masks

Following a court hearing last month, attorney J.W. Carney Jr. told reporters that Bulger was never an FBI informant. Carney still insisted that Bulger had an immunity agreement with now-deceased prosecutor Jeremiah O’Sullivan.

In court documents filed Friday, prosecutors say Bulger’s “mystifying” claim that he was never an informant is contradicted by more than 700 pages of informant reports on Bulger in the FBI’s files.

MORE NEWS: Massive Wind-Whipped Fire Spreads To Several Salisbury Buildings

Copyright 2013 The Associated Press.