An OPP officer faces perjury and criminal negligence charges following an investigation by Ontario's police watchdog into an ATV crash in Dawn-Euphemia last summer.

Members of the Special Investigations Unit (SIU) arrested OPP Const. Sean Coughlan Friday after SIU director Tony Loparco determined charges should be laid against the officer following the agency's investigation into the crash.

Coughlan has been charged with two counts of perjury, two counts of obstructing justice, and one count each of criminal negligence causing bodily harm and obstructing a police officer, according to an SIU release Friday.

Coughlan was released from custody Friday on an undertaking given to a peace officer. He is expected to appear in Sarnia court Feb. 28.

All of the charges laid against Coughlan stem from a collision last June when Coughlan was working at Lambton OPP's Petrolia detachment.

On the evening of June 22, 2016, the SIU says, a 24-year-old man was driving an ATV when he was involved in a collision with a vehicle and suffered serious injuries.

After the crash, Lambton OPP reported at the time an officer on patrol that night had come across a vehicle travelling at a high rate of speed eastbound on Bilton Line in Dawn-Euphemia.

The officer then continued the patrol and discovered an ATV already rolled over into the south ditch of Bilton Line, police said at the time.

The ATV driver – who was lying on the roadway – had life-threatening injuries and was taken to hospital, according to police.

OPP technical traffic collision investigators were called to the scene of the crash. Bilton Road, between Annett and Kerry roads, was closed for several hours to allow for an investigation into the cause of the collision.

In its press release Friday, the SIU stated it will not be making any further comments about the case in the interests of ensuring a fair trial for the accused.

The SIU is an arm's-length agency that investigates reports involving police that result in death, serious injury or allegations of sexual assault.

More to come.