August 27, 2012 (KEYESPORT, Ill.) -- Authorities expect to resume their search for two boaters who presumably drowned in a southern Illinois lake.

Investigators say the men went missing from a motorboat on Carlyle Lake on Saturday, and search efforts that day and Sunday failed to locate them. The search was to resume Monday.

Illinois Conservation Police Sgt. Eric Manker says the men had been boating with a third friend when one of them jumped into the lake and began struggling. That's when the other victim went into the 26,000-acre lake in trying to help.

Manker says the third person remained in the boat, but it drifted away and he didn't know how to operate it.