A veteran Lincoln police officer is dead after collapsing at a gym and being rushed to a hospital.

Officer John Clarke died Monday after collapsing at a fitness facility. The cause of the 43-year-old’s death wasn’t immediately clear.

Clarke had been part of the Lincoln Police Department for 21 years. He served as the lead trainer for the canine unit and worked as a canine handler for 15 years.

Lincoln Police Chief Jim Peschong says Clarke was an accomplished officer with many commendations.

For instance, Clarke received an award in 1999 for his efforts to find a missing Alzheimer’s patient. Clarke continued searching the area long after the search was called off for the night and ultimately found the victim.

Clarke is survived by his wife, Lisa, and three children.