Jury convicts 29-year-old of murdering man in motor home

A Spokane County jury convicted a 29-year-old man Friday of stabbing and killing a sexual partner, 58-year-old Anthony Plumb, in April 2021.

Zane McDonald, wearing a brown suit, will be sentenced in early May.

During closing arguments Thursday, prosecutors said the two men were engaged in a sexual relationship and that Plumb, three decades older than McDonald, was providing money and a place for the younger man to stay.

Defense attorneys argued that Plumb took advantage of the younger McDonald, threatened him with violence if he didn’t submit to sex, and told jurors there wasn’t enough evidence that McDonald stole from Plumb after a fatal struggle with a knife.

Prosecutor Dale Nagy said McDonald knew Plumb as an older man with money.

According to Nagy, McDonald initially told investigators Plumb loved him and that the two were planning on spending their lives together.

Plumb, however, also tried to keep McDonald a secret from his friends and family, Nagy said. McDonald planned to blackmail Plumb’s family with information about their relationship in an effort to get money from him, Nagy said.

According to court documents, McDonald was aware of Plumb’s safe, which was believed to have contained at least $10,000 before money was taken from it.

McDonald had a drug habit that cost him about $100 each day, Nagy said.

“This was a robbery. It went bad,” Nagy said. “That night, Mr. McDonald was going to steal from Mr. Plumb. He killed Mr. Plumb in the course of that robbery.”

Plumb was found dead with a stab wound on his neck two days after McDonald visited his RV.

McDonald was located later in a stolen Jeep. Police located keys to Plumb’s RV and keys to the safe inside of the Jeep.

Forensic scientists also found McDonald’s fingerprints on the safe.

Defense attorneys for McDonald argued that Plumb took advantage of the younger man. Plumb had provided McDonald a place to stay for the night and made a separate bed space in his RV, but he also made two sexual advances on McDonald, defense attorney Kirsten R. Svendsen said. McDonald testified that Plumb demanded sex from him at knife point, attorneys said.

McDonald “redirected” Plumb’s knife during a struggle, Svendsen said.

“It was likely a split-second decision,” she argued.

Svendsen also said that authorities did not thoroughly investigate another man who received money from Plumb.

McDonald killed Plumb in an act of self-defense, they argued, but he did not steal from the safe, Svendsen said.

Svendsen said McDonald likely didn’t say anything about Plumb’s sexual advances because he was embarassed and ashamed.

Nagy, however, argued that contradicts McDonald’s previous statements about the two men’s relationship.

Families of Plumb and McDonald were not in the courtroom Friday, but Plumb’s family watched the verdict via Zoom, according to Nagy. Svendsen declined to comment about the jury’s guilty verdict.

S-R reporter Garrett Cabeza contributed to this report.