Friends remember Ocia Mae Chamberlain as a kindly, 40-year-old woman who went to church and put food on trays for patients at Walter Reed Hospital. She was not, they say, the type of person who had enemies.

But one Saturday morning in May, as Chamberlain was about to get into her car and go to work, a man walked toward her and shot her five times, leaving her dead on the street.

"It shocked people very much," said Irving Bruce, a truck driver who lives next door to Chamberlain's two-story brick house at 1507 Anascostia Ave.NE. "If someone is running around the streets all the time, you expect something to happen to them. But Ocia isn't someone who went out. She just worked all the time."

D.C. homicide detectives Charles Schular and Dwight K. Vasey say the Chamberlain murder has been their most perplexing case in recent years.

"It does not have the earmarks of a robbery or a sexual attack or a mugging," said Schuler. "It was an execution-type murder. Someone was planning to kill her, and we don't know why."

The Chamberlain murder is one of 28 homicide cases in which a suspect has not been arrested out of 154 cases this year. This year, suspects have been arrested in 82 percent of the murders; last year, suspects were arrested in 70 percent of the murders.

The detectives believe they might be able to figure out who killed Chamberlain if they can find the witness who phoned the homicide squad the day of the murder -- May 26, 1979. The witness did not leave his name.

The witness told a homicide detective that while he was driving to work at 5:30 a.m., he saw a man on Anacostia Avenue NE striking a woman who was bleeding and wearing a white nurse's uniform. The assailant then ran into a car parked on a nearby street.

"The man probably saw it just after the shooting," said Schuler. "We need to find out what he saw in detail."

The detectives have tried to find the man by stopping cars that drive along the 1500 block of Anascostia Avenue and asking drivers whether they saw Chamberlain or her assailant that fateful day. None have said yes.

Meanwhile, Chamberlain's estranged husband, Jasper, a truck driver for Safeway, and her four teenage daughters live in the brick house on Ancostia Avenue wondering when the detectives will find the murderer.

"It's so strange," says he daughter, Eartha Lee, 18. "Who would kill someone right in front of their house? I just hope they find him."

Chamberlain had been separated from her husband for three years. She lived with her four teen-aged daughters in the house on Anacostia Avenue NE. Her husband lived in a room on Massachusetts Avenue SE.

The two had separated, her husband says, because she "always put me down. She didn't seem to have no interest in me.

"Look at everything you see in this house here," he says, as the gestures toward the television set and chairs in the living room. "These are the hands that did it. I never heard a compliment or anything."

Around the time that Chamberlain was murdered, her husband told police, he was eating breakfast at the Fireside Truck Stop on Rte. 301 in Anne Arundel County. Several persons at the truck stop told detectives that they saw him there.

He says he cannot figure out why anyone would want to kill her. "I really would like to know," he shrugs.

The two met when they were teenagers in South Carolina. They went to the same church and the same high school. They moved to Washington soon after they were married. He worked as a construction worker, a porter and a taxi driver. She worked as a cleaning woman.

"She worked most of he life," said her husband. "Occasionally, she didn't work, when the children were being born."

For the last several years, she worked in the cateria at Walter Reed Hospital, putting or bread and butter or milk on the trays that moved past her.

"We'd kid around about what we'd be d oing on our off days," says a coworker, Emma Precia. "She'd say, 'I'm going to stay in bed all day,' or 'I'm going to do my cooking, my washing and my ironing.'"

One of Chamberlain's supervisors remmbers her as a prompt, diligent worker who was easy to get along with.

On Sundays, Chamberlain would usher men and women into the pews at Southern Friendship Baptist Church on Minnesota Avenue SE. Whenever women in the church were ill, she would visit them. And whenever someone in the church died, she and other members of the church Flower Club would arrange to have flowers sent to their families.

"We were heartbroken when we found out she was killed," said Rev. Coley Johnson. "She was a very nice person and very respectful. Everyone liked her. I don't see how anyone could hate her."