PITTSBURGH — A federal public defender says his client will be charged with a crime in the four-year-old case of a pizza deliveryman who was killed by a bomb locked onto his neck.

The attorney, however, asked a judge on Monday to prevent prosecutors from holding a news conference to announce the indictment of his client, Marjorie Diehl-Armstrong.

Public defender Thomas Patton was appointed to represent Diehl-Armstrong in September after she had repeatedly been interviewed by investigators in the 2003 death of Brian Wells. The 46-year-old pizza deliveryman died in an explosion shortly after robbing a suburban Erie bank with a bomb that had been locked onto his neck by a crude metal collar.

Though Patton doesn't say in his emergency motion for a gag order how or why Diehl-Armstrong will be charged, the attorney wrote, "it is anticipated that an indictment will be forthcoming shortly."

Diehl-Armstrong, is serving seven to 20 years in prison for pleading guilty but mentally ill to killing her boyfriend, James Roden, in 2003.

Roden's killing led police to question Diehl-Armstrong in the Wells case because Roden's body was found in the freezer of William Rothstein. Rothstein, who has since died, lived near the TV tower where Wells was sent to deliver his last pizza the day he died.

A law enforcement official speaking on condition of anonymity told The Associated Press that a news conference announcing charges in the case was tentatively set for Wednesday. The official spoke on condition of anonymity because the event has not been formally announced.

Patton said publicity generated by such a news conference could prevent Diehl-Armstrong from getting a fair trial, noting that USA Today and TV shows such as "America's Most Wanted" have already covered the case.

No hearing was immediately scheduled on Patton's request.

Wells was caught shortly after robbing the bank on Aug. 28, 2003, and spoke with police as he sat handcuffed in a parking lot, waiting for a bomb squad to arrive.

He told police that he had been accosted by gunmen who locked the bomb on his neck at the TV tower and forced him to rob the bank. The device exploded before the bomb squad made it to the scene.

Wells' family has said they believe he was just an innocent victim. But authorities have refused to say whether he was a victim or a conspirator.