Prosecutors charge Kent couple with murder, arson in death of woman found in burned car

Denise Kay Grigsby. - COURTESY PHOTO, King County Sheriff
Denise Kay Grigsby.
— image credit: COURTESY PHOTO, King County Sheriff's Office

King County prosecutors filed murder and arson charges Wednesday against a Kent couple in connection with the murder of a 39-year-old Kent woman found in the trunk of her burned-out car near Black Diamond.

Prosecutors charged Michelle Backstrom, 34, with second-degree murder and second-degree arson for the death of Denise Kay Grigsby. Prosecutors charged Kennon Fastrup, 30, who dated Grigsby and also is the boyfriend of Backstrom, with second-degree arson, first-degree rendering criminal assistance and attempting to elude a pursuing police vehicle.

Backstrom is in the county jail in Seattle with bail set at $1 million.

Senior Deputy Prosecutor Kristin Richardson stated in the charging papers her reasons for the high bail request.

"Backstrom is a methamphetamine user who admitted to the prolonged, extremely violent beating and strangulation of her supposed friend, to destroying evidence - including Denise's body - and to attempting to flee the area to avoid capture," Richardson wrote. "She is unemployed and was released from prison just two years ago after a conviction for vehicular homicide."

Backstron also has convictions for attempted forgery, drug possession, driving offenses and car theft.

Fastrup is in the county jail at the RJC in Kent with bail set at $1 million.

"Fastrup is also a methamphetamine user," Richardson wrote in court documents. "He has pending, unrelated charges of violation of a no-contact order and violation of the uniform firearms act."

Fastrup also has convictions for attempting to elude, assault and drug and firearms violations.

The two are scheduled to be arraigned at 9 a.m. May 31 in Courtroom GA at the Norm Maleng Regional Justice Center in Kent.

King County Sheriff's Office detectives continue to investigate the case. Deputies arrested the couple May 11 along Interstate 90 in North Bend after a high-speed car pursuit. The couple reportedly had been staying in the woods near I-90 after the killing and car fire.

The murder allegedly occurred May 4 at the home of Backstrom on the East Hill after an argument between Fastrup and Grigsby, whose body was found May 6.

Shortly after 4 a.m. May 6, Mountain View Fire and Rescue responded to a report of a car fire in the area of Southeast 328th Street and Southeast Auburn-Black Diamond Road. When the fire department arrived the car was fully engulfed in flames. Fire investigators discovered the burned remains of Grigsby in the trunk of the car.

The body was burned to a point where the gender or any other characteristics could not be determined by observation alone, according to charging papers.

Detectives determined Grisby as the registered owner of the burned car. They found out through interviews with relatives and friends of Grigsby about her connection to Fastrup and Backstrom.

Meanwhile, the King County Medical Examiner's Office determined that Grigsby died from blunt force trauma to the head. They also determined she died before the car fire because she had no soot in her respiratory system. They identified her through dental records.

Detectives used cellphone records to connect Fastrup to being near the car fire within minutes of the fire.

Detectives interviewed the couple after their arrest. Fastrup confessed to burning the car at the arson site. He claimed he did it at the request of Backstrom. He said he did not know Grigsby was dead or that her body was in the trunk until they actually got to the scene and he opened the trunk. He said he burned the car anyway to assist Backstrom.

Fastrup denied participating in the murder and claimed he had left Backstrom's house at the time of Grigsby's murder.

Backstrom confessed to detectives that she had participated in the murder and arson. An argument among the three at Backstrom's East Hill home in the 25000 block of 128th Place Southeast reportedly led to the killing of Grigsby.

An argument broke out in the kitchen between Fastrup and Grigsby. Backstrom then entered the kitchen when the argument turned physical. Backstrom told detectives that as she tried to break up the fight, Grigsby bit her thumb, which hurt and upset Backstrom. The fight between the two women continued in the garage where Backstrom punched Grigsby in the head. She claimed Fastrup hit Grigsby in the head with a metal cylinder from a Maglight flashlight.

Fastrup then reportedly used a metal cable to strangle Grigsby. But Backstrom later said she believed Grigsby died from a head injury and not strangulation.

Detectives used a search warrant at Backstrom's home and found blood spatter in the kitchen and garage consistent with Backstrom's story. They found Grigsby's driver's license inside of Backstrom's purse after searching Backstrom's car used in an attempt to flee along I-90.


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