A King County Superior Court judge handed down the 254-month sentence Friday against Gary Wade, 42. He was convicted last month of second-degree murder for the killing of Michelle Thornton, who was found dead in the closet of her Belltown apartment on Jan. 6, 2011.
The prison term, at the highest end of the standard sentencing range, was handed down after the Thornton's father and other family members spoke out in court.
Evidence at the scene suggested there was a struggle and that Thornton had been sexually assaulted, investigators said. The medical examiner determined Thornton, 43, had been strangled to death.
Footage from building security cameras, fingerprints and DNA evidence led Seattle police detectives to Wade, who is a convicted felon. He was arrested on Feb. 26, 2011.
When questioned by detectives, Wade admitted he knew Thornton as he often sold her drugs. He initially said he'd last seen her before Christmas 2010; however, when investigators confronted him with evidence, he said "when he last saw Ms. Thornton, she was dead and that he had placed her in her closet," according to court documents.
Thornton was last seen alive on Dec. 29, 2010, when she last used her debit card. Records show she made a call on Dec. 30, but failed to report to work on the same day. Her family reported her missing on Jan. 4, 2011.
Prosecutors said Wade has a long criminal history in several states including Florida, Georgia and Utah. In Washington state, he was previously convicted of making a false or misleading statement to a public servant and possession of cocaine.