Authorities on Monday are continuing to search for a man on the Kasilof River after the boat he was in overturned Sunday.

The incident was reported to Alaska Wildlife Troopers in Soldotna on Sunday, troopers said in an online statement. The caller told troopers that she was able to make it back to shore after the boat overturned, but that 67-year-old Charles Nikolas of Kasilof had not.

Wildlife troopers responded along with Alaska State Parks rangers and Central Emergency Services, searching on land and with boats, troopers said in the statement. A helicopter was also sent from Anchorage to help with the search, troopers said.

Crews did not find Nikolas, and called off the search for the day at 8 p.m. Sunday, troopers said. The operation resumed Monday, with wildlife troopers and Alaska State Parks continuing to search with the helicopter, a boat and crews on the ground.

This is a developing story. Check back for updates.