SLIDELL — Authorities are looking for a Baton Rouge couple missing Wednesday while boating near the Louisiana-Mississippi state border, a Louisiana Department of Wildlife and Fisheries spokesman said.

Officials are looking for William Holloway, 63, and his wife Kathy Holloway, 61, on the Bogue Chitto River in the Bogue Chitto National Wildlife Refuge in St. Tammany, spokesman Adam Einck said.

Officials were notified of a capsized, 14-foot aluminum flatboat on the river that a passer-by discovered, Einck said.

The Department of Wildlife and Fisheries has taken the boat in custody for investigation, Einck said.

Wildlife and Fisheries was called about the missing couple around 10 a.m. Wednesday, Einck said. Family members last heard from the couple around 3 p.m. Tuesday.

What happened between those times is still uncertain, Einck said.

The Holloways were camping on the refuge and still had their vehicle parked at a boat launch on the Pearl River Navigational Canal off Lock No. 3 Road, Einck said. The Holloways’ possessions also were still at their campsite.

Authorities plan to search through the night depending on weather conditions, Einck said. The U.S. Fish and Wildlife Services is assisting.

St. Tammany Parish deputies are helping the LDWF search in the northeast corner of the parish, Capt. George Bonnette said. They have sent boats and helicopters to help the search efforts, Bonnette said.