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Sole person charged in 2021 double murder with ties to Oil Springs released
May 13, 2026
Heather Wright/The Independent
A man charged after a body was hidden in Oil Springs over four years ago, has been released.
Matthew Theriault plead guilty Monday to two charges related to the murders which took place in his Sarnia apartment. Theriault plead guilty before Superior Court Justice Russell Raikes to one count of accessory and one count of committing an indignity to two bodies after failing to notify police when he found the bodies in his home just before Christmas 2021.
When Theriault was arrested Dec. 28, 2021 in Oil Springs, he was charged with two counts of second-degree murder and two counts of indignity to a body.
The Crown and his defense counsel agreed the murder charges should be dropped and Theriault, 47, should be released after serving four years and four months.
Little has been released about the murders of Lance Richardson, 31, and Jelani Byers-Coates, 18, since Theriault’s arrest. Monday, court heard Theriault knew Byers-Coates, but not Richardson and was not at home when the two were murdered.
In Dec. 2021, Theriault lived in a basement apartment on Watson Road in Sarnia. He was struggling with a fentanyl addiction.
Early that month, Byers-Coates began staying with Theriault, paying for his stay with fentanyl. It was a familiar arrangement, according to the statement of facts, which says Byers-Coates had stayed with Theriault a number of times for several weeks at a time.
Near the end of the month, Richardson arrived in Sarnia and asked to stay as well. Theriault didn’t know him, but agreed to let Byers-Coates’ friend stay temporarily.
On Christmas Eve, Theriault came back to his apartment and noticed the lock on the door was broken. He called out to his visitors, but received no response.
He went down the stairs and saw the shape of a body wrapped in a tarp. Theriault recognized Byers-Coates shoes next to the tarp.
The agreed statement of facts said it was clear to Theriault that Byers-Coates was dead and he had been murdered.
Instead of calling the police.,Theriault left the apartment and didn’t return for four days. He had decided to take the body and bury it. He cleared out his black Ford Escape, pulled Byers-Coates body up the stairs, through the front door and put the body in the back of his car.
Theriault went back inside to collect things he thought were evidence of the murder including a cartridge casing from the floor of the living room and a roll of wire which appeared to have been used to secure the tarp around the body.
“Mr. Theriault was aware that by removing of the body of Mr. Byers-Coates, the cartridge casing, and the wire from the residence, he was impeding the ability of the police to investigate the murders, and charge the murder. In doing so, he aided the culprit in evading police detection,” said the statement of facts read out in court.
While Theriault was inside, he found Richardson’s body in the bedroom. It was clear he was dead and had been murdered.
An autopsy showed both men had been shot in the back of the head with a single .22 caliber bullet.
Theriault decided he would go back for Richardson’s body. He headed out to his car with a shotgun .
The agreed statement of facts says he drove around for some time, stopping once to try to dig a hole to bury Byers-Coates. Shortly before noon on Dec. 28, he was in Oil Springs. He stopped his vehicle on Crooked Road and went into an outbuilding.
The owner say Theriault leaving and yelled that he wasn’t supposed to be there. Theriault went back to his car, drove away, turned around and came back to the owner, who was standing with several other men at the time.
Theriault put the shotgun on the passenger seat and got out of the car, telling the men he was leaving and there was no need to call the police. He also told them who he was.
The OPP were called to Crooked Line around 12:11 pm to deal with the man who had broken into the building. The officers were later told the man had a gun.
Officers spotted Theriault standing beside the vehicle around 12:30 pm in a laneway in front a residence. They watched as Theriault removed an item wrapped in a white blanket from the car and go into an out building. He exited the building with nothing in his hands. Theriault surrendered to them without incident, with his hands up.
Officers found a shotgun wrapped in a white blanket in the building and arrested Theriault for pointing a firearm and break and entre. He was taken to the Petrolia OPP station.
When he was searched police found a cartridge casing Theriault removed from his home. Forensic tests found it was a .22 caliber cartridge case.
Police searched his car and found Byers-Coates body. They went to Theriault’s house on Watson Road and found Richardson’s body.
Forensic examination was not able to identify whether the bullets removed from the two men during the autopsy were from the same firearm as the casing police found in Theriault’s pocket. The firearm Theriault hid in an Oil Springs outbuilding was tested and excluded as the firearm that killed Byers-Coates and Richardson.
Another gun found at Theriault’s home was neither excluded or confirmed to be weapon which killed the men.
Theriault has been in jail since being arrested. People who are held in jail prior to a trial are given credit of 1 1/2 days for every day served. Since Theriault was in jail during the pandemic, the Crown and defense lawyer agreed he had already served seven years.
After his guilty plea, Theriault was free to leave.
Questions to Lambton OPP about murders and whether any headway has been made finding the culprit were not returned by press time.
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