An 18-year veteran of the Lethbridge Regional Police Service (LRPS), his wife, daughter, and granddaughter were killed in a horrific head-on collision.

The crash happened just before 11 p.m. Friday on Highway 509, approximately 18 kilometres north of Standoff, when a Ford Taurus carrying the police officer and his family and a Dodge Ram pickup truck collided head-on.

46-year-old Cst. Sheldon Twigg, his 40-year-old wife Kim, 21-year-old daughter Lacey, and three-year-old granddaughter Brielle were all pronounced dead at the scene of the crash.

The driver of the truck, a 55-year-old man from Standoff, was airlifted to Foothills hospital where he remains in critical condition.

Cst. Twigg was the first Aboriginal member of the LRPS to be hired as a full-time officer.

"This is a tragic loss for our police service and a devastating loss for the Twigg family," said Police Chief Tom McKenzie. "Our thoughts and prayers are with the Twigg family."

Twigg was the Diversity Resource Officer for the LRPS and worked as a liaison between the police service and all cultures in the community. He previously worked as a patrol member and School Resource Officer.

Prior to joining LRPS, Twigg was a member of the Blood Tribe Police Service for two years. He also spent 15 years as a bull rider. In 1988, he was the Chief Mountain Rodeo Association bull riding champion and qualified for the World Classic Finals Rodeo. In 1989, he qualified for the Indian National Finals Rodeo. During his rodeo career Twigg also qualified for the Indian Rodeo Cowboys Association Region One Finals eight times.

Police are still trying to figure out the cause of the crash, but say alcohol does not appear to be a factor.

Members of the LRPS Victim/Witness Services Unit are helping other officers and family members cope with the loss.

Cst. Twigg and his wife Kim are survived by two teenaged sons.

Funeral arragements will be announced once they have been finalized.