ERIE, Pa. -- One of the suspects in a bizarre robbery attempt in which a man was killed by a bomb locked around his neck pleaded guilty in federal court today.

Kenneth Barnes, 54, is to be sentenced in December for his role in the robbery of a PNC branch near Erie. He entered pleas to conspiracy to commit armed bank robbery and abetting the use of the collar bomb.

Another suspect, alleged mastermind Marjorie Diehl-Armstrong, remains to be tried.

Prosecutors today also said the victim of the bomb, Brian Wells, was heavily involved in the planning of the robbery. On Aug. 28, 2003, Mr. Wells, a pizza delivery driver, was called to a remote location where his accomplices were waiting. However, he tried to back out of the plot when he realized the collar device was locked and the explosives were live.

Prosecutors indicated a gun was fired near Mr. Wells to get him to comply.

After police stopped his car following the robbery, Mr. Wells told them the bomb was live but that black men had abducted him and forced him to wear the device. Prosecutors indicated no black men were involved.

Police handcuffed Mr. Wells and ordered him to sit on a street but the bomb exploded before a bomb squad could arrive.