Prince George's County corrections officials said yesterday they are investigating the possibility that nine inmates had help from inside the county detention center in making their escape early Wednesday.

Corrections spokesman James O'Neal said Prince George's authorities have enlisted the help of the D.C. police fugitive squad, U.S. marshals and FBI agents in checking what he termed "promising leads.".

O'Neal said investigators are checking the possibility that a hacksaw blade, apparently used to cut through bars on a window, was smuggled into the jail by a corrections officer. He also said they are checking reports that an officer patrolling the perimeter may have been wearing headphones all night.

"We're considering anything that may have impeded the officers, visually, mentally or otherwise," said O'Neal. "Having a radio on would certainly block his auditory process."

He added that there was no evidence of improper behavior by guards.

A law enforcement official involved with the investigation said, "It's quite possible (that) not just the guards but (other jail) personnel" aided the escapees. "They had to have had assistance. I can't imagine a hacksaw blade being born in a jail--it had to be brought in.".

All nine prisoners were awaiting trial--seven on armed robbery charges, one on a drug charge and one on a charge of violating probation.