Published October 29, 2013, 07:32 PM

NEWPORT, Minn. — Authorities believe accidental carbon monoxide poisoning is what killed a man who was working on a gas engine in his garage in the Twin Cities suburb of Newport.

Emergency crews were called Friday afternoon to the garage where 60-year-old Robin J. Hiley was found not breathing. A gas-powered stump grinder was running in the garage when emergency crews arrived at about 4:30 p.m., according to the police report.

Police officers, and later paramedics, attempted CPR on Hiley, but they could not revive him and he was pronounced dead at the scene.

Police Chief Curt Montgomery said it’s believed Hiley died of carbon monoxide poisoning. The garage doors were closed while the engine was running.

“It wasn’t intentional; it just happened,” Montgomery said.

Hiley’s black labrador dog Jack also was found unresponsive in the garage, police said. The dog was taken to the University of Minnesota veterinary hospital for emergency care but later died.

The Ramsey County medical examiner’s office is handling the autopsy.

Problem:  running vehicle in garage