Authorities are trying to determine if impairment led to a car crash in Gilbert that left the son and granddaughter of Pinal County’s sheriff dead.

Twenty-two-year-old Cooper Lamb and his 1-year-old daughter were declared dead on the scene after being T-boned by a pickup truck.

Lamb’s fiancé, who is the mother, was sent to the hospital with life-threatening injuries. 

The driver of the truck was arrested on suspicion of a DUI. Governor Doug Ducey sent his condolences to Pinal County Sheriff Mark Lamb.