WALKER COUNTY, Ala. (WIAT) — The father of a missing 5-year-old boy in Walker County, Alabama, has been taken into custody after explosive materials were found in his home during a search, authorities said.

The FBI is assisting to ensure the scene is safe before authorities execute a search warrant. Police say they have also found explosive materials from past detonations in the woods, which is making the search more difficult for safety reasons.

The child — Johnathan Boley of Jasper — was last seen about 11:30 a.m. Dec. 31 in the 7000 block of Highway 195. He was wearing a yellow Mickey Mouse shirt, black pants and Paw Patrol shoes.

Authorities have used drones equipped with thermal imaging but have not detected heat signatures indicating the child is in the woods, Walker County Sheriff Nick Smith said. He added that Boley’s 6-year-old brother last saw him crossing under a fence.