ST. JOHNS COUNTY, Fla. -- Personnel from the St. Johns County Sheriff's Office and the St. Johns County Marine Rescue continue to search the ocean near the Matanzas Inlet for a swimmer missing since 1:30 p.m. Sunday.

Sheriff's Deputies told Channel 4 witnesses said a 25-year old man was in the ocean with a group of friends from Gainesville. He had a boogie board and was swimming with a woman -- a former lifeguard -- who also had a boogie board.

Investigators said the two were a good distance from the shore and in rough water when the man lost his grip on his boogie board. Authorities said he grabbed onto the woman's board, but then lost his grip and disappeared under water.

"He lost a hold of the board and was last seen submerging," Sgt. Stephen Briggs told Channel 4's Diane Cho.

Deputies said they found the board, but by nightfall, there had been no sign of the missing swimmer.

Rescue efforts resumed Monday morning. The sheriff's office helicopter and marine units were assisting, along with the personnel of the U.S. Park Service.

Deputies are not releasing the name of the victim, pending the notification of his next-of-kin. Authorities said he is from Haiti, so that process could take some time.