(CBS) -- Defense attorneys in the James "Whitey" Bulger racketeering trial will likely attack the credibility of star prosecution witnesses in opening statements, which could come Wednesday, experts say.
Bulger, the alleged leader of Boston's "Winter Hill" crime gang, is accused in a broad indictment of a long list of crimes, including 19 killings, extortion and money-laundering. Authorities say he committed the crimes while he was an FBI informant, but Bulger's lawyers deny that he was ever an informant.
Speaking to the jury, the defense may seek to attack the motives of prosecution witnesses who've been convicted of crimes, California criminal defense attorney Michael Cardoza told CBS News' Crimesider.
"In opening statements, the defense will lean heavily on the type of witnesses the prosecutors are putting on, and whether they can be trusted or not," Cardoza said.
One star prosecution witness, John Martorano, is already the source of contention between prosecutors and the defense team. Bulger's defense argues prosecutors are involved in a "cover-up" of alleged crimes committed by Martorano, a former hitman turned government witness, since his 2007 release from federal prison.
Martorano was alleged to be a hitman for the Winter Hill gang, and admitted to killing 20 people. He served 12 years in prison after cutting a deal with the federal government to act as a witness.
Bulger's defense attorneys allege a state police officer said his attempts to investigate Martorano were "stymied" by a state police lieutenant, one of the lead investigators on the Bulger case. They've asked a judge to delay opening statements, and the issue prompted a heated exchange in a Boston courtroom Tuesday.
The defense would likely seek to detail the criminal backgrounds of witnesses with convictions and lay out for the jury "what's in it for them," Cardoza told Crimesider.
Bulger associates including former partner Stephen "The Rifleman" Flemmi and former aide Kevin Weeks are also expected to testify.
Bulger fled Boston in 1994 and spent 16 years on the run, one of the FBI's most wanted fugitives, before his arrest in California in June of 2011.
A jury of 18, including six alternates, was seated Tuesday. Jurors won't be sequestered in the highly-publicized case, but their identities will be kept secret and they'll be referred to only by number.
The trial is expected to last three to four months. During jury selection, U.S. District Judge Denise J. Casper told potential jurors that she recognized serving on the panel may pose an "extreme hardship," but that she must balance the needs of jurors with Bulger's right to get a "cross-section of the community" to sit on the jury.
Bulger has pleaded not guilty.