BATON ROUGE (AP) — A federal trial could start this summer for three men who claim they are victims of cruel and unusual punishment because of the decades they spent in isolation cells at the Louisiana State Penitentiary, their attorney said.

The lawsuit was filed in 2000 in U.S. District Court in Baton Rouge on behalf of two Angola inmates who were first placed into isolation cells in 1972 and a third inmate who spent 29 years in isolation before his conviction was overturned and he was released in 2001. A pretrial conference is set for April 17.

The three men, who have become known as the Angola 3, are Robert King, Herman “Hooks” Wallace and Albert Woodfox. Wallace and Woodfox remain in isolation at Angola. King, who used to go by the last name Wilkerson, has resided in Austin, Texas, since Hurricane Katrina.

King was placed in isolation for allegedly killing a fellow inmate, but that conviction was overturned in 2001 and King pleaded guilty to a lesser charge.

Wallace and Woodfox, who had formed a chapter of the Black Panther Party to fight sexual slavery and other problems inside the prison, were convicted of killing correctional officer Brent Miller during a riot on April 17, 1972.

King said Monday that Woodfox and Wallace were targeted because they were “activists” and because there was a need to quickly resolve Miller’s killing.

Prison officials have maintained the men pose a security risk at the prison. On Monday, Assistant Warden Angie Norwood said Warden Burl Cain would have no comment.

The organization known as the Innocence Project has ramped up publicity about the case recently.

Barry Scheck, co-founder of the Innocence Project, said Monday “there are a lot of good reasons they didn’t commit this crime at all.” New Orleans attorney Nick Trenticosta said a bloody fingerprint found at the scene where Miller was stabbed 32 times does not match Woodfox or Wallace, who were serving sentences for armed robbery at the time of Miller’s stabbing.

Trenticosta said about 200 inmates had access to the room where Miller was killed, but the Department of Corrections has made no effort to find the person whose finger left the print. In addition, Trenticosta said Department of Corrections officials have also been unwilling to turn over to defense attorneys the fingerprint cards for the 200 men who had access to the room.

Trenticosta also said he has tried to get fingernail scrapings taken from Miller after his death, but Department of Corrections officials said those scrapings have been lost. Police take scrapings from under a victim’s fingernails to determine if a fight occurred and the assailant’s skin was torn away by the victim’s fingernails.

Wallace has filed a motion in state court asking that his conviction be overturned and life sentence set aside because he claims a key witness received a promise of a pardon if he testified against Wallace and Woodfox at trial.

Nineteenth Judicial District Commissioner Rachel Morgan recommended that Wallace get a new trial, but state District Judge Mike Erwin rejected that recommendation last year. The case now sits at the state 1st Circuit Court of Appeal.

Woodfox has a similar appeal in U.S. District Court in Baton Rouge.