BUCKSPORT (AP) — A reverend and well-known Maine health care advocate had been under investigation before his body was recovered from the Penobscot River, state police said Monday.

An investigation of the Rev. Robert Carlson began last Thursday, said Steve McCausland, spokesman for the Maine Department of Public Safety. He did not give the nature of the investigation.

The Bangor Daily News reports that the Katahdin Area Council of the Boy Scouts of America had received a letter about Carlson that included allegations of child abuse.

Boy Scout leaders at Katahdin Area Council said they had turned the letter over to state police on Monday and referred any questions about its contents to the Maine State Police.

“The Katahdin Area Council is presently unaware of any such allegations concerning Scouts past or present,” Daniel Lee, Kathadin Area Council president, told the Bangor Daily News.

The investigation started at the request of the district attorney’s office after it had received a letter, McCausland said.

About six people had been interviewed so far, McCausland said, but Carlson, 68, was not one of them.

Carlson’s body was found Sunday morning in the river in Bucksport after his car was found abandoned on a bridge.