PASADENA, Calif. (AP) _ Police searched today for a man who slipped away in a hail of gunfire after briefly abducting three people and crashing their car into a guard shack at a NASA research center, authorities said.

The three hostages escaped unharmed Thursday as police opened fire at the gunman at the Jet Propulsion Laboratory.

Timothy M. Howze, a 36-year-old janitor employed by a contractor at the laboratory, vanished inside a building and remained at large today, said police Sgt. Mike Kirkpatrick.

Mary Randall, who was abducted with her parents, Arthur, 77, and Magdalena Randall, 74, said Thursday that Howze told them believed he was going to die.

''He said he didn't want to kill us, that he didn't want to kill anybody in the car, but that he knew he was going to be killed sometime today,'' said Ms. Randall, 38, of Altadena.

A special weapons and tactics team sealed off a cluster of JPL buildings, but failed to find the gunman. Police did recover a handgun.

''We've searched everywhere and it's over,'' Los Angeles County sheriff's spokesman Bob Stoneman said Thursday evening. ''There's a real possibility that he got out before the containment was set up.''

Officers at one point were within a few feet of him, but he slipped away, said police Sgt. Davis Harris.

Howze, who was under police surveillance and wanted for investigation in 14 recent armed robberies, had been spotted by officers Thursday morning during a lumber company robbery, Harris said.

He ran onto a freeway, where he commandeered his hostages' car, with police pursuing it to the lab.

Police opened fire as he ran into a JPL office building, while other officers aided the three hostages.

Johnny Guerino, a JPL construction foreman, said he was entering the grounds in a pickup truck and saw a young man carrying a revolver.

''I haven't heard that much gunfire since I was in Vietnam,'' Guerino said.

It was unknown if the gunman fired any shots.

As some JPL scientists and employees huddled in their offices, instructed not to leave until the siege ended, officers narrowed their search to a cluster of buildings at the north end of the 76-acre complex. About 6,000 JPL workers in other buildings were sent home early.

Various witnesses reported seeing a man dart in and out of buildings at the complex, but police were not able to capture him and called off the search of the lab complex 7 1/2 hours later.

JPL, home of America's unmanned space exploration program, is operated by the California Institute of Technology for the National Aeronautics and Space Administration.