Master thief Bernard C. Welch, the fugitive murderer of Washington cardiologist Michael Halberstam, was recaptured early today by police responding to a routine parking complaint in Greensburg, Pa.

Welch, 45, had been the object of a nationwide manhunt since May 14, when he and Hugh T. Colomb, another convicted murderer, escaped from the sixth-floor maximum-security area of a high-rise prison in downtown Chicago. The two smashed their way through a slit-like window and a concrete outer wall and slid 75 feet down an extension cord to the ground.

Welch was apprehended at about 3:30 a.m. by two Greensburg policemen who found him asleep in bed in an apartment he was renting under the name of Robert Wilson. A young woman identified as Janice Roos was with him, police said.

Several hours elapsed before police learned that "Wilson," arrested on suspicion of auto theft, was one of America's most hunted criminals. Police said a search of the car after he was taken into custody turned up a stolen pistol, two stolen rifles and stolen jewelry, indicating that Welch had resumed his life as a carriage-trade burglar.

Howard Safir, director of operations at the U.S. Marshals Service, told a Washington news conference today that Welch was being taken under heavy guard to the Marion, Ill., federal prison, one of the nation's most secure penitentiaries, and his arrival there was reported this evening. He had been confined there in 1981 but had been moved to less secure facilities after allegedly telling federal prosecutors that he had information about white neo-Nazi activists at Marion and other prisons.

Tonight, Halberstam's widow, Elliott Jones, told the Associated Press: 'm exhilarated, needless to say. I wasn't afraid or anything like that. [But] I could not stand the idea of his being out there somewhere, being free after my husband had given his life to catch him.

The arrest was the result of an unlikely chain of events that includes an irate neighbor, thorough police information, and bungling by Welch, who committed thousands of flawless burglaries in the Washington area in the 1970s to support a millionaire's life style.

He was convicted in D.C. Superior Court of first-degree murder for fatally shooting Halberstam, who surprised Welch in a burglary at the physician's Northwest Washington home on Dec. 5, 1980. Welch fled the house and shot Halberstam when he pursued.

Halberstam, the brother of Pulitzer Prize-winning journalist David Halberstam, headed for Sibley Memorial Hospital by car. Accompanied by his wife, Elliott Jones, he spotted Welch in the street and ran him down. The cardiologist, a respected physician and writer, then lost consciousness and the auto hit a tree. Welch was arrested at the scene, and Halberstam died later at the hospital.

After being sentenced to 143 years in prison, Welch vowed to escape. He had escaped from a New York State prison in the early 1970s and was considered extremely dangerous.

Lawmen who had studied Welch's long criminal career had predicted that he would settle in an out-of-the-way community under a false identity and attempt to live quietly while re-arming himself and resuming his criminal life. Their attention had been drawn to southern California and similar places where life's daily pace would be fast enough for Welch, with his taste for flashy cars and swank houses.

Greensburg, about 200 miles west of Washington and 25 miles southeast of Pittsburgh, is a small, residential town that will mark its 200th birthday next year -- an unlikely spot for a man who had a big house in Great Falls, Va., and ran two smelters in his basement to melt the silver and gold he stole from affluent Washington homes.

But the Marshals Service, which had been leading the hunt for Welch, said it had been zeroing in on the Pittsburgh area because of a rash there of more than 65 recent burglaries in which rare coins, antiques and other expensive items were taken. There apparently had been no report from the area of a sighting of Welch -- or of Colomb, who remains at large.

The serious-minded ways of small-town America may have been most responsible for the fugitive's capture. The story began about midnight Tuesday when an irate resident of Greensburg, population 17,000, complained to police -- apparently saying that two cars were parked, one behind the other, in a single space behind an apartment house on West Newton Street.

Patrolman Paul Burkey, a nine-year veteran of the 29-member police force, responded and found two cars, a Toyota and a 1977 BMW sedan. In interviews today, Burkey said a license-plate check on the Toyota identified Roos as the owner, and he knocked on the door of her third-floor apartment. When she answered, Burkey said, she told him that the BMW blocked by her Toyota belonged to her boyfriend.

Burkey left and radioed a routine license-plate check on the BMW to state police headquarters. Police computers reported that the plate had been stolen from a car in Carlisle a few weeks earlier. Suspicions fully aroused, Burkey radioed the BMW's serial numbers for a check.

The national crime information system reported that the luxury car had been stolen in Milwaukee in May. Although it was late, residents curious about the presence of the police gathered around. They told Burkey and his partner, Officer Joseph Niedzalkoski, that the car was driven by a Robert Wilson.

By that time, three or four more patrol cars had arrived, and Burkey and Niedzalkoski approached the apartment, their service revolvers holstered. They knocked again, and Roos answered, saying, according to Burkey, "This is no longer funny. I'm getting tired of this."

"Using my flashlight, I could see him lying in bed," Burkey said. "I could see his hands lying on his stomach, so I didn't feel at the time there were going to be any problems. I walked in and turned the lights on and identified myself as a policeman.

"He had one eye open, and he was watching me. But there were two of us policemen there, and he really gave up very calmly."

Wearing only undershorts, his reddish hair long and curly, Welch quietly dressed in slacks, shirt, socks and tennis shoes that the police inspected first for weapons. With Roos watching in bewilderment, they cuffed his hands behind him, Burkey said.

As they led him away, he turned to her and said, "Well, this is it. I guess it's over." He asked if he could kiss her goodbye.

No charges had been filed against Roos tonight. In the past, Welch has kept his criminal activities hidden from the women he lived with.

Locked in a cell at the City Hall jail, Welch refused to identify himself, and police called the FBI.

"We realized we had a vehicle that was stolen from out of state, and we felt it would be a good idea to get the FBI involved," said Burkey, 36, who has a journalism degree and worked at the daily Greensburg Tribune-Review for many years before changing professions.

Agent Hilary Jenkins of the FBI's Greensburg field office arrived about 4 a.m. and began questioning Welch and reviewing fugitive information. After a while, Welch "coughed up who he was," an FBI source said.

Safir said police reported that Welch told them he "was in the Witness Protection Program and asked them to call the Marshals Service in McLean, Va." Jay Stephens, a senior Justice Department official, said Welch had been moved from the Marion prison as part of the "protected prisoners" program to prevent reprisals against him.

Burkey had long since gone home to bed by the time Greensburg police realized that Welch was a dangerous fugitive. Told by an out-of-town reporter that he had arrested Halberstam's killer, Burkey replied, "Incredible."