In a bid for a new trial, attorneys for Terry L. Nichols said today that prosecutors and investigators failed to produce thousands of documents that could have helped his defense in the Oklahoma City bombing trial.

A prosecutor countered that the documents in question would not have affected the outcome of Nichols's trial.

Nichols, 44, was convicted in 1997 of conspiracy and involuntary manslaughter in the bombing of the Alfred P. Murrah Federal Building. He is serving a life sentence.

Prosecutors claimed Nichols helped his former Army buddy Timothy J. McVeigh finance the plan, gather the ingredients and mix the bomb used in the April 19, 1995 blast, which killed 168 people and injured hundreds of others. (McVeigh has appealed his own death sentence on murder and weapons convictions.)

Defense attorney Michael Tigar said prosecutors still have not turned over about 50 percent of the evidence -- about 43,000 so-called lead sheets from the FBI -- and that he is entitled to review them to try to justify a new trial for Nichols.

The sheets are used to record information from informal interviews or from callers during an investigation. Dozens of lead sheets were given to defense attorneys, but not until Dec. 11, 1997 -- just 12 days before Nichols was convicted.

Prosecutor Sean Connelly argued that "there is no legal or factual basis" for turning over the documents or giving Nichols a new trial because the documents would not have changed the outcome.

U.S. District Judge Richard Matsch, who presided over the original trial, said he would have to study the documents and would issue a ruling later.

One sheet, written shortly after the bombing, reported that Michael Fortier "advised that McVeigh purchased racing fuel at a race track in Kingman (Ariz.) and had rented his own shed there."

Tigar has told Matsch in the past that he never challenged the prosecution's contention that the racing fuel was purchased at a track in Texas because prosecutors never acknowledged they had conflicting evidence.

Prosecutors spent a lot of time at Nichols's trial trying to prove that he was in Texas at the time the fuel was purchased.

Tigar says he has other sheets showing that McVeigh plotted the attack with a group of associates operating around Kingman, rather than with Nichols, and evidence that Roger Moore, a gun dealer who claims he was robbed, had changed his testimony. Prosecutors contended that the guns were stolen by Nichols and McVeigh to finance the bombing.

Fortier pleaded guilty to having advance knowledge of the plot to bomb the building. He testified against McVeigh and Nichols, admitting that he helped McVeigh move and sell stolen weapons and lied to FBI agents.

Fortier was sentenced to 12 years in prison. The 10th U.S. Circuit Court of Appeals recently ordered a new sentencing hearing.

CAPTION: Terry L. Nichols is serving a life sentence for his role in the April 1995 bombing in Oklahoma City.