Prosecutors charge Auburn man in killing of autistic youth

Published 11:58 am Wednesday, April 8, 2015

King County Prosecutors have charged 42-year-old Matthew Christenson of Auburn with killing the severely autistic son of the woman with whom he lived in a Highline-area apartment for eight months in 2014.

Although the King County Medical Examiner’s Office initially determined that 18-year-old Otto Smith had died from natural causes, detectives with the King County Sheriff’s Office Major Crimes Unit continued their investigation after his mother admitted to them that she’d lied and that Christenson had killed her son.

This charge is in addition to charges that Christenson had subjected Smith’s younger brother to hours-long ice baths and forced marches in the stairwell of their apartment. He remains jailed and has pleaded not guilty to all charges.

The official account of what happened in that one apartment paints a terrible picture of wanton acts of malignant cruelty, including all-night ice baths, forced, pointless marches up and down the apartment building’s stairwell that lasted for hours and forcing the boys to live in the bathroom and sleep on the floor there.

Acts that “by design did cause such pain and agony as to be the equivalent of that produced by torture,” according to prosecutors.

Prosecutors in January charged Christenson with one count of second-degree assault domestic violence and one count of unlawful imprisonment domestic violence.

According to court records, the woman, a former teacher. reported that in April of 2014, feeling lonely and depressed, she placed an ad on Craig’s List seeking male companionship.

And met Christenson.

“In no time, Christenson moved himself into her life and into her home,” court records say, and “she reported that he quickly took over her life and controlled her behavior.”

According to court records, Christenson did not want the woman on medication and told her to stop taking an anti-depressant. According to court records, the woman and Christenson drank heavily and smoked marijuana, and Christenson told her that “her kids were evil and put evil spirits in their apartment.”

According to court records, investigators found the woman “seemingly unable or unwilling to stop the abuse or protect her child,” including the alleged ice baths.

Asked to explain the ice baths, the woman speculated that “it was to reduce the swelling and bruising from the beatings Christenson inflicted,” according to court records.

According to court records, during the early morning hours of Sunday, April 13, 2014, the woman called 911 to report that her 18-year-old son was not breathing. She later called back and cancelled the call, advising the dispatcher that “they were going to transport Otto to the hospital themselves.”

According to court records, Smith was taken to St. Francis Hospital in Federal Way where he was pronounced dead in the emergency room. According to court records, the woman told doctors and later the King County Medical Examiner’s Office that her son had accidentally fallen down some stairs

According to court records, the events came to light on Dec. 22, 2014 when deputies with the King County Sheriff’s office met with the boy’s mother at Tacoma General Hospital, where she had gone en route to Eastern Washington in an attempt to escape the abusive relationship.

At first the woman told officers she’d been kidnapped, but that story did not hold up for long.

During a later conversation with a social worker, according to court records, the woman claimed her boyfriend, Christenson, had killed her 18-year-old autistic son and that she had helped clean up the evidence.