Welcome to benjamin Oluwasegun's Blog: Chris Harper Mercer, Oregon Gunman, Is Recalled as a Recluse Close to His Mother

“He and his mother were really close,” said Ms. Lucumi, who estimated that Mr. Mercer and his mother, who shared a small one-bedroom apartment in Torrance, lived there for less than a year. “They were always together.”

Bryan Clay, 18, said he once asked Mr. Mercer why he wore “a military get-up” every day.

“He kind of just didn’t want of talk about it” and changed the subject, Mr. Clay said.

“He didn’t say anything about himself,” he added.

Derrick McClendon, 42, another former neighbor, said that Mr. Mercer was so timid and ill at ease that on occasion he would ask him if something was wrong.

“I would say, ‘Hey, man, you all right?’ ” Mr. McClendon said. “He would say ‘hi,’ but that’s it. He was really shy.”

Mr. Mercer appeared to have sought community on the Internet. A picture of him holding a rifle appeared on a MySpace page with a post expressing a deep interest in the Irish Republican Army. It included footage from the conflict in Northern Ireland set to “The Men Behind the Wire,” an Irish republican song, and several pictures of gunmen in black balaclavas. Another picture showed the front page of An Phoblacht, the party newspaper of Sinn Fein, the former political wing of the I.R.A.

A picture of Mr. Mercer also appeared on a long-dormant dating website profile registered in Los Angeles. On it, he described himself as an “introvert” with a dislike for “organized religion.”

In the offline world, Mr. Mercer’s mother sought to protect him from all manner of neighborhood annoyances, former neighbors in Torrance said, from loud children and barking dogs to household pests. Once, neighbors said, she went door-to-door with a petition to get the landlord to exterminate cockroaches in her apartment, saying they bothered her son.

“She said, ‘My son is dealing with some mental issues, and the roaches are really irritating him,’ ” Julia Winstead, 55, said. “She said they were going to go stay in a motel. Until that time, I didn’t know she had a son.”

Rosario Espinoza, 33, was once a neighbor of Mr. Mercer’s and moved into the apartment that the mother and son shared when the two moved from Torrance a couple of years ago. She said that the two “kept to themselves,” but that from time to time Mr. Mercer’s mother would complain that Ms. Espinoza’s young children were playing too loudly and bothering her son.

“They’re normal children that play, but she would get really upset,” Ms. Espinoza said. “It was during the daytime. But I guess the noise would really upset him, the son.”

Other neighbors said she would confront them about their barking dogs when they returned from work. “She would wait till they got home and knock on their door,” Kim Hermenegildo, 48, said.

Ms. Espinoza said that she heard Mr. Mercer’s mother got a job in Oregon, prompting the family’s move north.

Mr. Mercer and his mother shared an apartment in Winchester, a dun-colored building that sat roped off behind police tape on Thursday evening, guarded by sheriff’s deputies who shooed away reporters.

Bronte Hart, a neighbor who said she lived in an apartment below Mr. Mercer’s, described a more assertive young man than his former neighbors in California did. Far from avoiding social interaction, she said, he frequently shouted at her for smoking on her balcony.

“He yelled at us, me and my husband,” said Ms. Hart, who lives in the building with her husband and father. “He was not a friendly type of guy. He did not want anything to do with anyone.”

Ms. Hart and her father, Eli Loomas, said the authorities came to the apartment complex and began asking questions about Mr. Mercer on Thursday morning. A woman who may have been his mother also showed up, they said, and she appeared distraught.

Another neighbor, a man in his 50s who declined to give his name, said that Mr. Mercer lived on the second floor of the three-story building with his mother. He said he believed they were both students.

“Chris was a good kid, you know,” he said, adding that he had spoken to Mr. Mercer only briefly over the last few years. “He’s always been polite to me.”

When asked if he had ever seen Mr. Mercer with firearms, the man demurred. “I’d rather not say,” he said.

Ian Lovett reported from Torrance, Calif., and Liam Stack from New York. Dirk VanderHart contributed reporting from Winchester, Ore.

TORRANCE, Calif. — Chris Harper Mercer, the man identified as the gunman in the deadly rampage at Umpqua Community College in Roseburg, Ore., on Thursday, was a withdrawn young man who neighbors said wore the same outfit every day — combat boots, green Army pants and a white T-shirt — and was close to his mother, who fiercely protected him.

Neighbors in Winchester, Ore., and Torrance, Calif., where Mr. Mercer, 26, lived with his mother, Laurel Harper, remember a reclusive and seemingly fragile young man with a shaved head and dark glasses who seemed to recoil from social interaction.

“He always seemed anxious,” said Rosario Lucumi, 51, who rode the same bus in Torrance as Mr. Mercer when she went to work. She said she believed he took it to El Camino College. “He always had earphones in, listening to music.”