An Alabama man holding a terrified young boy hostage in an underground bunker might not be giving up any time soon, authorities said.

Police were negotiating through a 4-inch ventilation pipe with the man, believed to be Jimmy Lee Dykes, 65,a Vietnam veteran and retired truck driver with a wicked temper and a history of threatening neighbors.

Authorities were tight lipped about the conversation with Dykes but said the hostage situation, which entered its fifth day on Saturday, might stretch on for a while. Dykes is holding a 5-year-old boy identified as Ethan who was snatched off a bus at gunpoint.