A 43-year-old Lewistown man is dead after being exposed to high levels of carbon monoxide.

According to the Frederick County Sheriff's Office, Deputy First Class Richard Matthews was sent to a home in the 6000 block of Putman Road to provide a domestic escort around 5:30 p.m. on Thursday.

When he arrived at the house, he looked through the garage window and saw a man unconscious, lying on the floor and could hear a lawn mower running.

Deputy Matthews forced his way into the home and with the help of a neighbor, pulled the victim outside and preformed CPR. The man was taken to Frederick Memorial Hospital where he was pronounced dead.

Deputy Matthews and the neighbor were both exposed to high levels of carbon monoxide and had to be flown to the University of Maryland Medical Center to be treated.

The investigation into what happened is continuing.