Peterson had faced as much as 60 years, but Judge Edward Burmila said he gave some consideration for his years as a police officer and his service in the military.
Peterson, who did not testify at this trial, made an emotional appeal to the judge, at times appearing to choke up. He began by telling the judge, "Good day, my name is Drew Peterson. I hope I don't aggravate the situation here, but I have a lot of things to be said." Then he screamed, "I did not kill Kathleen!"
"Yes, you did," a woman said.
"Ma'am, I'd like you to leave the courtroom," Burmila said. "And Mr. Peterson, don't make any outbursts that are designed to aggravate people."
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"I'm sorry, your honor. I must have been woozy," Peterson said.
Peterson said he was the victim of an unjust and invasive police investigation that ignored or lost evidence that could have shown his innocence.
Peterson bitterly complained that the Rev. Neil Schori, who testified, betrayed his promise never to repeat anything that was said by him or his missing fourth wife, Stacy.
Peterson, 59, was convicted last fall of drowning his third wife in her bathtub.
In arguing for a maximum sentence, Will County State's Attorney James Glasgow reminded the judge about the damage done to his young children with Peterson's missing fourth wife, Stacy. Prosecutors have said they believe Peterson killed Stacy and could seek charges in that case.
"Not only is their mother gone, but also their father is gone, as he sits before you," Glasgow said.