Defense attorneys in the murder trial of Oklahoma City bombing conspirator Terry Nichols (search) cross-examined the prosecution's star witness Thursday, seeking to convince jurors that Michael Fortier (search) is an unreliable witness who had his own connections to the bomb plot.

Fortier, who served in the Army with Timothy McVeigh (search) and knew both men, told Nichols' lawyers he was given stolen weapons that were allegedly sold to finance the April 1995 bombing.

When defense attorney Brian Hermanson asked Fortier if he believed his involvement with Nichols was suspicious, he responded, "Yes, I would agree to that."

Nichols and McVeigh were convicted of federal charges for the deaths of eight federal agents. McVeigh was executed in 2001 and Nichols is serving a life prison sentence. Nichols is now being tried in state court for 161 murder charges for the other victims and for a fetus of one of the victims. He could be sentenced to death if convicted.

Fortier previously said he was not involved in the bomb plot. But he acknowledged Thursday that he shared money from the sale of the stolen weapons with McVeigh. He also said he handled blasting caps and other bomb components and even accompanied McVeigh on a trip to case the Alfred P. Murrah Federal Building (search) four months before the blast.

Fortier has been given immunity in exchange for his testimony. He has testified that McVeigh told him Nichols was deeply involved in the bomb plot, stealing explosives and committing a robbery to help pull off the attack on the Oklahoma City federal building. Fortier is serving 12 years in prison for knowing about the plot and not telling authorities.

Hermanson sought to downplay Nichols' role, asking Fortier whether McVeigh thought Nichols was "stupid."

"He made comments like that," Fortier acknowledged.

Defense attorneys contend that McVeigh manipulated Nichols, and that their client was set up to protect unknown coconspirators who were more involved in planning the bombing.