An intense manhunt for a retired special forces soldier accused of shooting his wife entered its fifth day Tuesday, as authorities continue to scour a section of northern Tennessee.

Authorities say Craig Berry, who is facing an attempted murder charge, fled into the woods. He is described by the Stewart County Sheriff's Office as having "extensive training in survival tactics."

"He is an excellent swimmer and diver, and is in good physical shape," the sheriff's office said, and noted he is familiar with the area in which he disappeared.

The sheriff's office said Berry is armed and believed to be carrying extra ammunition. He was wearing camouflage clothing when he was spotted on a nearby trail camera several days ago, the sheriff's office said.

The sheriff's office said it doesn't believe Berry has a phone, but investigators also haven't ruled out the possibility that he has received outside help after the alleged shooting.

The sheriff's office said it is working with the U.S. Marshals Service, the Tennessee Bureau of Investigation and the Tennessee Highway Patrol, and plans to conduct a "very detailed search" of an area on the eastern side of Kentucky Lake this week. 

Stewart County Sheriff Frankie Gray said finding Berry could be a "lengthy process." 

Berry has been on the run since the early morning hours of May 1, when deputies responded to a report that Berry's wife had been shot during a domestic dispute. She was hospitalized at the time, and her condition Tuesday was unclear.  

Stewart County is located along the border with Kentucky, some 75 miles northeast of Nashville.