OKLAHOMA CITY ? Michael Fortier, the government’s star witness in the Oklahoma City bombing case, returned to the witness stand Monday to testify for state prosecutors who want Terry Nichols sent to the death chamber for his role in the attack.

Fortier, speaking in a courtroom crowded with bombing survivors and federal marshals, said bomber Timothy McVeigh told him in October 1994 that he and Nichols planned to blow up the Alfred P. Murrah Federal Building and revealed details of the bomb plot.

“He discussed how he would take ammonium nitrate and fuel and mix it up and put it in 55-gallon drums,” Fortier said.

Fortier said he and McVeigh traveled to Kansas on a trip in which they stopped in Oklahoma City and drove around the federal building. Fortier said McVeigh targeted the building because he believed “that’s the building where the orders came out of for Waco.”

McVeigh was a guest at Fortier’s home outside Kingman, Ariz., on and off for two years after the April 19, 1993, siege of the Branch Davidian compound in Waco, Texas. Prosecutors said the Oklahoma City bombing was a twisted effort to punish the government for the siege in which 80 people died.

Fortier said McVeigh knew people would be hurt or killed in the bombing. McVeigh analogized their deaths to the loss of stormtroopers in the movie “Star Wars,” Fortier said.

“All of the people may not be individually guilty,” he testified McVeigh said. “But because they work for the evil empire, their deaths would be justified.”

McVeigh was convicted of federal murder charges for the bombing, which killed 168 people. He was executed in June 2001.

Fortier said McVeigh told him in a telephone conversation that Nichols had tied up an Arkansas ammunition dealer, Roger Moore, and robbed him at gunpoint.

He said that McVeigh gave him some of those stolen weapons, which he sold at gun shows in Nevada and Utah. Authorities said the stolen weapons helped finance the bomb plot.

Nichols is the focus of a preliminary hearing, now in its second week at the Oklahoma County jail, that will determine whether there is enough evidence to try him on 160 state counts of first-degree murder. Prosecutors plan to seek the death penalty.

Nichols is serving a life prison sentence on federal conspiracy and involuntary manslaughter convictions for the deaths of eight law enforcement officers in the bombing.