The 12-member jury that convicted bombing conspirator Terry Nichols on state murder charges will consider whether Nichols should be sentenced to death or life in prison.
The second phase of Nichols' trial was scheduled to get under way Tuesday with prosecutors questioning survivors of the Oklahoma City bombing and members of victims' families.
The panel of six men and six women found Nichols guilty of 161 counts of first-degree murder on Wednesday just five hours after they began deliberating a verdict in the case.
Jurors also convicted him of first-degree arson and conspiracy to commit arson in the April 19, 1995, bombing of the Alfred P. Murrah Federal Building, which 168 people and injured hundreds more.
Judge Steven Taylor told Nichols' jury that the penalty phase of the trial will resemble a separate trial, with opening statements by prosecutors and Nichols' defense attorneys, witnesses questioned by both sides and closing arguments.
The penalty phase of Nichols' trial is expected to last about three weeks. Jury selection for Nichols' trial began on March 1, and testimony began on March 22.
Prosecutors will question dozens of bombing survivors and victims' relatives about the impact the bombing had on their lives.
Nichols' relatives, including his mother, Joyce Wilt, and sister, Suzanne McDonnell, are expected to plead for his life. Nichols didn't testify in his own defense but could still take the stand during the penalty phase.
Prosecutors presented evidence that Nichols bought the explosive ammonium nitrate fertilizer used in the homemade bomb and stole detonation cord, blasting caps and other explosives.
The defense contended others helped executed bomber Timothy McVeigh carry out the bombing and Nichols was the fall guy for a wider conspiracy.
Nichols, 49, was acquitted of federal murder charges in 1997 but convicted of conspiracy and involuntary manslaughter charges in the deaths of eight federal law enforcement officers in the bombing. He was sentenced to life in prison.
Oklahoma prosecutors charged Nichols in 1999 with the deaths of the 160 other victims and one victim's fetus.
Taylor barred prosecutors from seeking the death penalty on the count involving the fetus after ruling prosecutors didn't give his defense attorneys adequate notice of their plan to seek the death penalty on that count.
Nichols' jury sentenced him to life in prison without parole on that count.