Authorities pulled a car from the Stono River on Thursday and found a man's body inside.
Charleston County sheriff's deputies say the red Nissan was last seen driven by 44-year-old Harold Foy of Charleston. The Coroner's Office still is trying to confirm the identity of the body and cause of death.
Foy has been missing since March 13, but authorities said they don't suspect foul play.
Divers from Charleston police and the Sheriff's Office started searching the river in front of the Sol Legare Boat Landing after receiving a tip through Crime Stoppers that Foy and his car might be in the river.
Divers entered the water by boat about 10 a.m. and almost immediately picked up a hit on sonar, said Charleston County sheriff's Maj. John Clark.
Divers went into the water close to the landing and found the car. The license plate matched the one on the car Foy was driving, Clark said.
He said it's probable that the car went in and out with the tide. If that's what happened, residents said, it wouldn't be the first time a car mistakenly drove into the river. Sol Legare Road is not well lit at night. A small white sign warns that the road ends.
According to an incident report, Foy last spoke to his fiancee on the phone about 11 p.m. March 13 and told her he was on his way home.