McALESTER, Okla. — Terry Nichols went on trial for his life Monday in the Oklahoma City bombing and was alternately portrayed as an eager participant in the attack and a fall guy in a conspiracy wider than the government has acknowledged.

Nichols hated the U.S. government and worked hand-in-hand with Timothy McVeigh in assembling and detonating the "huge, monstrous bomb," prosecutor Lou Keel said during opening statements in the state murder trial.

"These two were partners, and their business was terrorism," Keel said.

Nichols, wearing a gray sport jacket over a white shirt, occasionally whispered to his attorneys but showed no emotion during the prosecution's opening statement.

Defense attorney Brian Hermanson countered that McVeigh and other conspirators were responsible for the bombing and Nichols was manipulated by McVeigh to take the blame.

"Timothy McVeigh set him up so McVeigh could cover up the others who acted in this conspiracy," Hermanson said.

Nichols, 48, is already serving a life sentence on federal changes for the deaths of eight federal law officers in the April 19, 1995, blast that killed 168 people. The state charges are for the 160 other victims and one victim's fetus.

Prosecutors brought the state charges in hopes of sending Nichols to the death chamber for his role in the bombing — the deadliest act of terrorism on U.S. soil at the time. McVeigh was executed in 2001.

Prosecutors allege that Nichols conspired with McVeigh to build the bomb in a plot to avenge the FBI siege against the Branch Davidian sect at Waco, Texas, exactly two years earlier.

Keel said Nichols bought 4,000 pounds of ammonium nitrate fertilizer for the bomb in 1994 and stole blasting caps to set it off. Nichols, who met McVeigh in the Army, also robbed an Arkansas gun dealer of weapons and gold and silver coins to help finance the plot, Keel said.

The blasting caps were stolen from a Kansas rock quarry and drill marks on a padlock at the quarry matched a drill bit found in Nichols' basement, he said.

The bomb was delivered in a Ryder truck that exploded outside the Alfred P. Murrah Federal Building. Prosecutors say Nichols helped McVeigh pack the bomb.

"This huge, monstrous bomb was detonated right in front of that building," Keel said. He said those not killed in the initial blast died because of glass that was sent "flying like bullets."

Keel said Nichols "had long been mad at the federal government" and was outraged by the siege in Waco that killed about 80 people.

Hermanson said prosecutors are relying heavily on "assumptions and circumstantial evidence." He said the state is going to "leave things blank" in its evidence against Nichols, who was home in Kansas when the bomb went off.

The defense plans to show that Nichols was a patsy for a shadowy group of conspirators, possibly including members of the white supremacist and anti-government group Aryan Republican Army.

"People will testify about seeing McVeigh, seeing him drive that truck, seeing him with other persons," Hermanson said.

"The evidence is going to show many people who saw John Doe No. 2," he said, referring to the mysterious alleged accomplice who some eyewitnesses saw with McVeigh on the day of the bombing.

The first prosecution witness was an FBI agent who searched Nichols' home two days after the bombing. Mary Jasnowski testified she found four 55-gallon drums that looked like the ones prosecutors say were used in making the bomb. She also testified that she found a receipt for 2,000 pounds of ammonium nitrate fertilizer and found small white bits of ammonium nitrate outside the house.

Also discovered was an address book containing the names and phone numbers of McVeigh's sister, Jennifer, and Michael Fortier, a former Army buddy of Nichols and McVeigh who is serving a 12-year prison sentence for knowing about the bomb plot but not telling authorities.

Before opening arguments began, two jurors and an alternate were excused because they are distant cousins of an attorney in the prosecutor's office, George Burnett. Judge Steven Taylor criticized prosecutors for "inexcusable conduct" in not revealing the links sooner.

Except for consulting on jury selection, Burnett is not prosecuting Nichols. But he is an assistant district attorney with the Oklahoma County district attorney's office, which is prosecuting the case.

District Attorney Wes Lane was out of state and unavailable for comment, his office staff said.

The trial will go on with 12 jurors and three alternates.

"Unfortunately, the court's plan to have six alternate jurors has been cut in half due to the inexcusable conduct by the state," Taylor said.

Taylor said that if there are further problems with the jury and he runs out of alternates, he will dismiss the case.

The trial had been moved 130 miles from Oklahoma City to McAlester out of fear that extensive media coverage and lingering pain over the bombing would make it impossible to seat a jury in Oklahoma City.

The trial is expected to last four to six months.