WALLA WALLA, Wash. – Christopher Monfort was convicted of killing Seattle police Officer Timothy Brenton in 2009. He was found dead in his cell Wednesday morning at the Washington State Penitentiary in Walla Walla, according to a spokesman for the state Department of Corrections.

Monfort, 48, was convicted in June 2015 of aggravated first-degree murder for the ambush killing of Brenton. He also wounded Brenton’s partner on Halloween night 2009. Monfort was serving a life sentence, according to The Seattle Times.

The convicted killer was paralyzed below the waist by a gunshot he suffered during his arrest six days later in Tukwila. He was in deteriorating health by the time of his trial.

Department of Corrections communications director, Jeremy Barclary said Monfort was found dead in his single-person cell at 7:45 a.m. Wednesday. Prison staff began CPR, but Monfort was pronounced dead by medics, he said.

There was nothing suspicious found in Monfort’s cell, and there were no indications of self-inflicted harm, Barclay said.

Brenton’s brother, Matt Brenton, was in a meeting when he received a text message Wednesday notifying him Monfort was dead.

“After the trial, we really didn’t think about him all that much,” said Matt Brenton, referring to his mother, Penny Brenton, and sister, Betsy Porter. “While this is not closure at all, it closes a chapter. We will, just as we’ve always done, be celebrating Tim and honoring Tim.”

Brenton admirably showed his humanity by offering condolences to Monfort’s family: “We know his family is hurting and mourning, and our thoughts are with them,” he said.

Monfort was also convicted of two counts of attempted first-degree murder for wounding Brenton’s partner, Britt Kelly, and, later, for pointing a handgun at a homicide sergeant investigating Brenton’s death, according to The Seattle Times.

Lastly, he was convicted of first-degree arson for setting a fire and detonating pipe bombs that destroyed a handful of police vehicles at the city’s Charles Street maintenance yard nine days before Brenton was killed.

He was found not guilty of attempted murder in the arson incident as prosecutors argued he intended to kill officers responding to the scene of the fire.

Monfort claimed insanity to all five charges. His attorneys said he believed he could end police brutality if enough police officers were randomly killed.

Monfort was sentenced to life in prison without the possibility of parole. He admitted, “I killed a good man,” during his sentencing.

He was left a paraplegic after he was shot twice when he pulled a gun on Seattle police Sgt. Gary Nelson, who was with two other homicide investigators following up on a tip about the car used in Brenton’s killing, when they encountered Monfort outside his apartment on Nov. 6, 2009.

The shooting occurred just as a memorial service for Brenton concluded at KeyArena.