After a tense, three-hour stakeout at a Waldorf motel, Maryland State Police yesterday arrested the accused murderer of a "good neighbor" who was going to the rescue of a screaming woman in the hallway of a Silver Spring apartment Monday night.

Robert Donald Smith, a 35-year-old Mitchellville resident, was charged with murder in the shooting death of 26-year-old Rich Ciavarella. Smith is being held without bond at the Montgomery County detention center and will be arraigned on the murder charge today.

According to police accounts, the shooting occured when Ciavarella, on hearing a woman's screams outside his apartment, grabbed a shotgun and stepped out into the hallway. There, police said, he encountered Smith, who was struggling with Claudia Sue Pinnow, a friend of Smith's estranged wife, whom Smith was trying to locate.

Smith then fired two shots from a .45 caliber pistol, fatally wounding Ciavarella, before leaving the scene with Pinnow in tow, police said. Later that night, according to police, Smith released Pinnow unharmed, found his wife, and drove with her to a Holiday Inn in the Southern Maryland city of Waldorf.

A team of plainclothes state troopers closed in on the Holiday Inn on U.S. Rte. 301 shortly after 9 a.m. yesterday, after being tipped off by two friends of the fugitive.

As police waited outside and evacuated the first floor of the motel, the two friends entered Smith's room. A short time later Smith, his wife and the two friends emerged from Room 114 and drove north on 301 in the fugitive's Mustang. The car was stopped at a roadblock two miles north of the motel, just across the Prince George's County line.

"There was no resistance," said state police spokesman Dan McCarthy. "He surrendered without any problem."

Patrick Foley, the manager of the Holiday Inn, said yesterday's stakeout "kind of shook us up."

Smith had checked into the motel at 5:30 a.m. Tuesday -- seven hours after the fatal shooting -- and registered under a false name with a matching credit card, Foley said. He ordered his meals from room service, the manager said, and briefly left his room Tuesday afternoon to ask for a telephone book.

Tuesday night, police said, a man identifying himself as "Robert Smith," telephoned two Washington television stations, saying he wanted to give himself up to "the media" rather than risk being arrested by police. But Smith never met with newsmen.

"Lord knows, the man was looking for help," state police spokesman Bill Clark said yesterday.

After being held for questioning in the Waldorf state police barracks, Smith -- wearing collar-length brown hair, a mustache and a blue and white ski sweater -- was taken to the Montgomery County Detention Center in Rockville. His wife, Barbara Jean Smith, was released unharmed yesterday after the ordeal.

At the time of the shooting, police said Smith was wearing a cast on one of his arms. When he fled, he removed the cast. Police took Smith to a local hospital last night where doctors restored the cast to his arm.

Police said a .45 caliber pistol, believed to be the murder weapon, was recover from the trunk of Smith's Mustang.

If convicted of the murder charge, Smith could face life imprisonment or the death penalty. Police said yesterday they were conferring with the state's attorney's office on the possibility of pressing additional charges, including kidnapping, against Smith.

Debbie Ciaverella, who was staying with her family in Altoona, Pa., yesterday, said she and her husband were watching television in their Silver Spring apartment shortly before 10 p.m. Monday night when they heard a woman screaming "Hello me, help me."

The cries were coming from Claudia Sue Pinnow, who lived across the hall, Rich Ciavarella, his wife said, grabbed an unloaded shotgun from under the couch and went out to the hallway to help the woman.

"When Rich went out the door, the door slammed and 'pow, the shot went off," Debbie Ciavarella said. Her husband was shot twice and died a short time later.

Claudia Sue Pinnow said she had never met Rick Ciavarella, who had lived in the apartment since last May.

"He should have stayed in the apartment," Ciavarelia's mother Grace said. "But it was his duty to do a good deed when a woman yells."