MONROE – An off-duty sergeant with the Waldo County Sheriff’s Department died after a diving accident in a pond behind the home of his boss, the county sheriff.

Sgt. Mark Schade was pronounced dead at Eastern Maine Medical Center in Bangor shortly after 9 p.m., according to state Department of Public Safety spokesman Steve McCausland.

Schade had been flown to the hospital by LifeFlight helicopter after members of the State Police dive team found his body under ice in a small pond behind Sheriff Scott Story’s home on Back Brooks Road in Monroe.

Schade, 42, was a 17-year veteran of the sheriff’s department and was diving while off-duty to help the sheriff clean a device to add oxygen to the private pond. Schade, who was diving alone, had brought the aerator to the surface where it had been cleaned and then had returned the device to the water, according to McCausland.

The sheriff and a second deputy saw Schade move under the ice, which was partially covering the pond.

The two called for help about 4:30 p.m. Members of the dive team recovered Schade’s body shortly before 7 p.m., under ice about 10 feet from shore. McCausland said.

An Androscoggin County sheriff’s deputy, David Rancourt, head of the county’s dive team, lost his life while diving for evidence in the Androscoggin River in November 2006.