A hunter whose body was found near Sundre was attacked by a grizzly bear, said the medical examiner's office in Calgary.

The man, tentatively identified as Don Peters, 51, had been missing since Sunday. His body was found in a heavily wooded area of the Ya Ha Tinda Ranch region, more than 175 kilometres northwest of Calgary.

"There was a firearm found with him and that was part of the identification that we used to come to our tentative conclusion. That weapon was discharged but we're still looking into exactly how it all fits into the situation," RCMP Sgt. Patrick Webb said Thursday.

The area where the attack happened has been closed off as fish and wildlife officers search for the bear.

"If in fact it was in that area but it decided to leave because of all the activity during the search, then there's a good chance it could be quite a ways away," said Dave Ealey, spokesman for Alberta Sustainable Resource and Development.

Ealey said he doesn't know what will be done with the bear when it is found because officials don't know exactly what happened yet.

The bear was likely a grizzly because they usually go into hibernation later than black bears, he added.

Peters's family issued a statement through the RCMP, thanking people who took part in the three-day search.