A 33-year-old SeaTac man faces a first-degree murder charge for allegedly beating his 55-year-old mother to death with a pipe wrench inside of her Kent home.

Duane Alan Bates is scheduled to be arraigned Aug. 19 at Maleng Regional Justice Center in Kent. Bates is in the King County Correctional Facility in Seattle with bail set at $3 million.

In the early morning hours of Aug. 3 at the Mar A Villa Mobile Home Park, 23810 30th Ave. S., on the West Hill, Bates reportedly viciously bludgeoned his mother to death in her bedroom with a pipe wrench and then covered her body with a plastic garbage bag and multiple blankets, according to charging documents.

Cathyrae Martini died of multiple blunt force injuries to the head, according to the King County Medical Examiner’s Office. The autopsy showed she suffered at least three blows to the head and that the implement used to inflict those blows was consistent with a pipe wrench.

Federal Way Police arrested Bates on the evening of Aug. 3 on an outstanding state Department of Corrections escape warrant. Bates was released from prison in June 2020 after serving an 87-month sentence on a Pierce County matter for first-degree burglary with a deadly weapon in 2014. He was on community custody at the time of his arrest. He violated his community custody conditions at least four times and was placed on escape status three times.

The next-door neighbors of Martini told Kent Police that the night before her body was discovered, Martini, Bates and Martini’s male roommate came over to visit. The three left at about 10 p.m. to return to Martini’s trailer. Bates reportedly had been staying at his mother’s trailer for a few days.

Bates came back to the neighbor’s trailer at about 1 a.m. and asked to borrow a pipe wrench, according to charging documents. The neighbor lent him a white pipe wrench. Later in the night, Bates returned the pipe wrench and the neighbor noticed a rust or blood-colored stain on the wrench.

Martini’s roommate told police Martini went to bed about 10 p.m. He said between 10 and midnight he heard two thump sounds coming from Martini’s room and Bates saying something to the effect of, “Oh no, mom.”

The roommate told police he then left the trailer to go back to the neighbors. He returned a short time later, knocked on the door and Bates answered, reportedly holding a wrench in his hand. Bates reportedly said, “I just put my mom to sleep.”

After the roommate went inside to grab his phone, he called out to Martini but didn’t hear a response. He said he returned to the neighbors again and then left the trailer park in his vehicle. He tried calling Martini several times between 1:27 and 1:40 a.m. but received no response. He said he then slept in his vehicle before leaving for work in the morning.

Detectives interviewed Bates and he told them he had got into an argument with his mother earlier in the day as she was being disrespectful. Later, he said he borrowed a pipe wrench from the neighbor, went to his mother’s bedroom and hit her with the wrench. He hit her the second and third times because she was still breathing. He said he then took the wrench back to the neighbor.

The mother of Martini’s grandchildren told police that she had exchanged Facebook messages with Martini the night of Aug. 2 about the kids visiting her the next day. She said she sent Martini a message about 8 a.m. on Aug. 3 but Martini didn’t respond.

A neighbor called 911 the morning of Aug. 3 after finding Martini under a blanket and with blood all over the house. Officers responded and found Martini deceased in her bedroom.