He was a familiar but not a forbidding figure in his suburban Prince George's County neighborhood, jogging early in the morning or working on his beloved Corvette racing car in his driveway during the day.

Edward Thomas Mann, accused of killing two men and injuring 10 others in a Friday shooting spree at the IBM building in Bethesda, is remembered on Michele Lane in Mitchellville as a friendly man who kept whatever problems he had to himself but who was always willing to help out a neighbor.

He was especially kind to the children on the block, several said yesterday. He let them play with the HO-gauge model train set that filled most of his basement along with four pinball machines that included a "shooting gallery." Sometimes, they said, he took them for rides in his blue Corvette with the name "Spiderman" on the side.

But he seemed to withdraw during the last year, children and parents said. On Halloween, for instance, he would often dress up as Frankenstein's monster to entertain them. Then, last year, there was no costume and a "no candy" sign posted on his door in the Brightleaf Knolls subdivision near U.S. Rte. 50 and the Beltway.

Mann had filed a discrimination complaint against IBM, his former employer, in January 1977, and it was dismissed that June by the D.C. Office of Human Rights for "no probable cause," according to the company. IBM, he told a WTOP radio reporter in a telephone conversation during the seven-hour siege, was "very prejudiced."

But his problems at IBM, where he worked as a salesman from 1966 to 1979, were unknown to many of his neighbors, some of whom said they were even unaware he had been unemployed. On his block, a dead-end street with 11 modest three-bedroom homes built about 1973, what they remembered most about Edward Mann was his pleasant disposition.

"The man always had a smile and a wave for somebody," said Robert Hunter, who lives around the corner on Saville Lane. "I'm the hotheaded one in the neighborhood. The man was just a general good Joe."

The Hunters recalled Mann's help in digging out the neighborhood during the blizzard of February 1979 and his mechanical help whenever a neighbor had car troubles.

"He was there when you needed him," said Georgia, Robert Hunter's wife. "He was never loud. I've never seen him drunk. He was just the person you'd like to have as a next door neighbor. He was so polite, so nice, so quiet. I trusted him completely."

Added 16-year-old Georgia Fae Hunter, "He's the kind of person you'd like to see the world full of . . . . It's like some horrible nightmare."

Edward F. Mazurowski, who lives across the street from Mann, described him as a "really super guy" with "no problems that I know of . . . . I didn't know the man that was in the IBM buiding. It was just . . . somebody else."

The Mazurowskis and the Manns--Ed and Rosa, his second wife--had gone camping together "numerous times," Carol Mazurowski said yesterday. She recalled one trip in which another family had brought along a pellet gun. Mann, she said, expressed disapproval. "He thought they were dangerous," she said.

"I've been in his house many times, and never saw any weapons or heard either one of them talk of owning guns," she said. "He was a very quiet, gentle person, very composed. I never saw him get riled up about anything."

His passion, everyone said, was cars. He and his wife had a Datsun sedan they drove for routine trips. There was also the rust-colored Lincoln Continental Mann drove through glass windows at IBM before allegedly starting his shooting spree. More than anything, though, Mann was a Corvette fan.

He and his wife, an administrative secretary to a dean at Gallaudet College, had two Corvettes, a blue one and a pink one. Mann raced the blue one frequently at Capital Raceway near Crofton, and he belonged to "Metro-Vettes," a District of Columbia car club he joined in 1973.

"He had the fastest car on the track," said club president James Butler. "He invested quite a bit in getting it track-ready." Like Mann's neighbors, Butler termed him "very mild mannered, very soft spoken and very cool, calm and reserved. He never raised his voice."

After Friday's news, Butler said he received as many as 50 calls from club members, all expressing shock. "Everybody said it was just totally out of his character. They said they couldn't believe Ed would do that."

Butler, an IBM employe who works in the building adjoining the data processing facility where the shootings occurred, said he knew nothing of Mann's problems with the company. "As far as I knew, he had a very good reputation" at IBM, Butler said. "He never discussed with me why he left."

Butler said he last saw Mann six months ago at Faces, a cocktail lounge on upper Georgia Avenue. "At that time, he was looking for a job. I gave him a couple of references," Butler said. The job leads, including one at Howard University, did not, however, pan out. "He called me back and said they were not offering as much as he was looking for," said Butler, who estimated Mann's IBM income at $40,000 a year.

Claudia Cannady, 35, knew Mann at Washington's McKinley High School, from which he graduated in 1962. She said they met again through the Corvette club. When it came to cars and work, she said, Mann was "very competitive in nature" but was unassuming in his dealings with people.

Cannady said Mann, tall and solidly built, had attended Morehouse College in Atlanta. She said they dated in 1975, after his divorce and before his second marriage. Mann has a teen-age son who neighbors said lives with his mother in the District.

Neighbors described Rosa Mann as an attractive woman who, when she became bored by her husband's automobile activities, often biked with the neighborhood children to a nearby store and bought them sodas.

Her husband suffered from allergies, neighbors said, and over the years he had often paid their children $2 to mow his lawn. This spring, however, the children said Edward Mann rejected their usual offers to do the job and the grass went uncut, although his wife did mow the front lawn once.

Friday morning, Carol Mazurowski recalled, she heard the IBM-bound Lincoln Continental start. It was a hard-starting car, she said, and she was fairly certain it had not been driven for some time.