KENT, Wash. - Police say an argument between members of a love triangle led to the grisly slaying of a Kent woman after a night of drug use.
Police said Kennon Fastrup was in a dating relationship with the victim, 39-year-old Denise Grigsby, and another woman, Michelle Backstrom.
According to probable cause documents, the three were using methamphetamine on the night of May 4 to May 5 at Backstrom’s home in Kent when an argument broke out between Fastrup and Grigsby in the kitchen area.
When the fight turned physical, Backstrom entered the room and tried to break it up when she saw the Grigsby was dominating Fastrup in the brawl, documents said.
As Backstrom got in between the couple, Grigsby bit her thumb, angering Backstrom, investigators said. When the fight moved into the adjoining garage, Backstrom pummeled Grigsby with her fists, police papers said.
Official police documents said Fastrup then grabbed a hard metal object and repeatedly struck Grigsby in the head. Both Backstrom and Fastrup then used a braided metal rope and a nylon lanyard to choke Grigsby until she was dead, probable cause documents said.
The couple then put Grigsby’s body in the trunk of her own car and drove it to a remote driveway at Southeast 328th Street and Auburn-Black Diamond road, police said.
Once there, they lit the car on fire and fled, documents said.
Grigsby’s body was found on May 6 by firefighters.
Backstrom and Fastrup were arrested following a police chase on Friday, officers said.
Documents said Backstrom confessed to the slaying and arson implicating Fastrup. Fastrup confessed to helping Backstrom dispose of the body and car in the arson, but said Backstrom killed Grigsby on her own when he was not in the house, police papers said.
Both face charges of arson and first-degree murder.