When Frank and Marilyn Flook moved to their Capitol Hill neighborhood last August, they acted like many other middle-class couples who move into an inner-city neighborhood these days.

They hung plants in the front bay windows. They planted grass and shrubbery in the front yard. For Christmas, they decorated their front door with tree branches and a wreath with a red ribbon. Their Christmas tree sparkled in the front window. To celebrate, they invited some neighborhood children into their home for cookies and punch on Christmas Eve.

Three days later, two young men attempted to force their way into the couple's home in the 1500 block of A Street NE, then shot Frank Flook to death. Police think the men, who fled with nothing, may have planned to burglarize the home.

The Flooks' black neighbors, who are upset by the killing, say they believe the couple was victimized because they were white.

Those intent on theft or violence in the neighborhood "single out the whites," said Vanessa Pegram, who lives two doors from the Flooks.

The Flooks were two of only three whites living in the block. The street is quiet and includes two-and three-story row houses owned by their occupants.

Pegram, sitting in her home, said a white couple who previously lived in the Flooks' house had been burglarized three times.

"Maybe the house was something like a red flag," said Henry McCartney, a friend of the couple."I just don't know."

"Nothing like [murder] has ever happened in our block," said Joseph Benson, the Flooks' next door neighbor and president of the A Street Block Club.

Marilyn Flook says she was awakened at about 9:30 p.m. Thursday by the constant ringing of the doorbell. After about 10 minutes, the ringing had become irritating, she said, so she went downstairs to see who was at the door.

"Don't open the door," she remembers her husband calling from their upstairs bedroom.

Mrs. Flook said that when she looked through the front bay window and saw a male figure, she mistook the young man for her paper boy. She went to open the door and, as she unlocked the dead-bolt lock, two men began pushing the door from the outside.

Struggling with all her weight against the door, she screamed for her husband, she said.

She said she had gotten the door almost closed, when her husband came running downstairs. One of the men reached around the door with a pistol and shot him once in the head.

Flook, who was unarmed, fell to the floor near the foyer. The two men fled. They had never said a word.

Marilyn Flook said she and her husband had moved to the neighborhood because "we felt that it was a nice, warm block and the people were nice. I couldn't ask for nicer neighbors."

"I don't know how I feel about the neighborhood now," she said.

Mrs. Flook, who works as a planning and development representative for the Washington area office at Housing and Urban Development, said she doesn't know if she will continue to live in the house.

She is reluctant to share her neighbors' speculation that there was anything racial in her husband's murder.

Police are similarly baffled, saying the intruders could have singled the Flook's residence out as a "white" house but said it was just as possible they simply chose a newly renovated house as one most likely to contain items of value. They believe the two men were trying to break in and rang the doorbell to see if anyone was at home.

They theorize that Flook may have been shot simply because one of the men panicked.

The Flooks moved here from Jacksonville, Fla. Frank Flook, 33, was an assistant manager at Gosnell's Garden Center in Landover Hills, Md.

"He was a hard worker," said Cathy Hall, Flook's co-worker. "He was very quiet and serious."

The Flooks had been married for 3 1/2 years. "He was one of the kindest persons I know," recalled Henry McCartney.