Police officers in Alabama are continuing in their efforts to negotiate the release of a five-year-old boy.
Police say Jimmy Lee Dykes, a retired trucker aged 65, shot dead a bus driver last Tuesday, and then abducted the child.
State police and other law enforcement officials are communicating regularly with the kidnapper, reportedly through a narrow ventilation pipe sticking out of the bunker.
The Vietnam veteran has been known to stay in his underground bunker for up to eight days.