Terry L. Nichols was even more "committed" than Timothy J. McVeigh to blowing up an Oklahoma City federal building nine years ago and played a bigger role in the crime, a prosecutor said Monday in closing arguments at Nichols's state-court trial.

"Nichols was the biggest contributor," Oklahoma County Assistant District Attorney Lou Keel told the jury. "He did everything possible to make sure Timothy McVeigh could blow up that building."

Keel said it was Nichols who methodically planned the deadly bombing with McVeigh, funding the conspiracy and acquiring the bombing components that McVeigh detonated on April 19, 1995, in front of the Alfred P. Murrah Federal Building, killing 168 people.

The men, prosecutors alleged during the trial, were motivated by a shared hatred of the federal government and plotted to avenge the 1993 federal raid on an armed religious cult near Waco, Tex.

In 1997, Nichols and his former Army buddy McVeigh were convicted separately for the deaths of the eight federal law enforcement officials who died in the explosion. McVeigh has already been executed for that crime, but -- to the disappointment of some relatives of the victims -- Nichols was convicted of manslaughter instead of murder and sentenced to life in prison.

Oklahoma prosecutors decided to try Nichols for murder and seek the death penalty.

He is accused of killing the other 161 victims, including an unborn child. Judge Steven Taylor has said that the jury may only consider first-degree murder or not guilty. If Nichols is convicted, the trial will immediately go into the penalty phase, where victims' relatives will testify.

Nichols, 49, sat expressionless in the courtroom Monday, as he had done through the months of his federal trial in Denver. The father of three was a farmhand in Michigan.

Defense lawyers have argued that Nichols was an unwitting dupe in the plot, set up to take the blame by McVeigh. They have also suggested McVeigh had other conspirators who were never charged. Nichols attorneys will give their closing arguments Tuesday, when the case will go to the jury.

The prosecution, which called 151 witnesses over 29 days, built a case similar to the federal one, alleging that McVeigh and Nichols meticulously planned the bombing for almost two years, using aliases, storage sheds and calling cards with fake IDs to cover up their actions.

Keel said Monday that even if others were involved, it doesn't exonerate Nichols. "It doesn't matter if there were two or 22 . . . you're still guilty," the prosecutor said.

Nichols was not in Oklahoma City the day of the blast, and there has been testimony suggesting that Nichols had backed out of the plot. But Keel reminded jurors that it is not enough for a conspirator to back out of a criminal plot to be exonerated -- he must try to stop it. Nichols, Keel alleged, took no steps to "prevent the crime."

Keel reviewed for jurors evidence that Nichols alone purchased 4,000 pounds of ammonium nitrate fertilizer, which when mixed with fuel, became the lethal bomb that blew up the building. And he reminded jurors that it was Nichols who made the first calls to try to find a vehicle to transport the drums filled with fertilizer.

The prosecutor also pointed to testimony that showed that detonating material stolen from a quarry in Kansas -- near where Nichols was living -- later was found in a search of Nichols's home. Keel said Nichols was the first among the conspirators to look for a way to transport the 55 plastic drums stuffed with explosives. Ultimately, McVeigh rented a Ryder truck.

Taylor said that the jury will be sequestered during deliberations, and he instructed them to bring enough belongings for two days.