More than three days after he allegedly shot a school bus driver dead, grabbed a kindergartner and slipped into an underground bunker, Jimmy Lee Dykes is showing no signs of turning himself over to police.

Hostage negotiators in Midland City, Ala., tried Thursday to persuade the 65-year-old retired truck driver to release the 5-year-old, who has Asperger's syndrome and attention deficit hyperactivity disorder.

But they acknowledged Dykes could hold out for days.

James Arrington is police chief of the neighboring town of Pinckard. He told reporters camped out at the site Thursday that Dykes has been known to hole up in the underground bunker resembling a tornado shelter for as many as eight days.

Dale County Sheriff Wally Olson said late Thursday that authorities were still communicating with the suspect.