The body of 62-year-old Benjamin Cowherd was found floating in the Chipola River near the Christoff Ferry Landing on Dec. 5.
Investigators say he was shot to death.
Money was found in Cowherd's pocket, but his wallet was stolen, and his credit card was used shortly after he was killed.
The card was used for gas twice within an hour at a Tom Thumb Food Store in Cottondale.
The suspect also unsuccessfully tried to use Cowherd's credit card at a local ATM.
Crimestoppers is offering a reward of up to $1,000 for information leading to the arrest of the suspect. The number is (850) 526-5000.