Lewis Shores' death has been ruled a suicide by the Arkansas Crime Laboratory.

Shores, 19, was the suspect in the deaths of Jimmy and Norma Grubb and his mother, Angela Shores. He was found unresponsive Nov. 29 in his cell at the Sebastian County Adult Detention Center and was pronounced dead that evening.

Arkansas Crime Laboratory medical personnel determined Shores' death was a suicide because a plastic trash liner was wrapped around his head at the time of his death and there was no evidence that anyone else was criminally responsible for the incident, according to a Sebastian County Prosecutor news release issued Friday afternoon.

Investigators on Sept. 5 developed Shores as a suspect in the double homicide of Jimmy and Norma Grubb after he allegedly fled a vehicle after a wreck Sept. 4 in the Booneville area. Logan County officials discovered the vehicle was registered to a man living in the 7700 block of Hermitage Drive and asked Fort Smith police to conduct a welfare check on the residence. During the welfare check, police found the Grubbs dead with blunt force trauma to the head, according to the probable cause affidavit.

After Shores’ arrest in September, police found his mother, Angela Shores, dead in an apartment in the 8200 block of U.S. 271 South. They searched for Angela Shores on Sept. 6 in connection with the investigation into the double homicide, according to Police Department news releases.