The next-door neighbor of a Capitol Hill man who was shot to death during an attempted break-in at his home in December was arrested last night and charged with murder in the incident.

D.C. police homicide detectives identified the suspect as Gregory Benson, 27, of 1523 A St. NE. Benson had been charged in a D.C. Superior Court warrant with a felony murder in the slaying of Frank Flook, of 1521 A St. NE, as Flook and his wife, Marilyn, tried to prevent two men from forcing their way into their home.

Police said Benson was taken into custody at his home about 10 p.m. without incident. He was being held without bond early today pending arraignment in Superior Court.

The killing of Flook, 33, provoked alarm and outrage among residents of the area, and friends and neighbors of the couple offered a $1,000 reward for information leading to the arrest of the killer. It could not be determined last night if anyone had claimed the reward.

Police sources said that Benson appeared in a court-ordered lineup at police headquarters several hours before the warrant for his arrest was issued, but investigators declined to say what information led them to identify him as a suspect.

They said Benson apparently lived with his parents at the A Street address and was unemployed, but were unable to provide further details on his background.

Flook, the assistant manager of a suburban Maryland garden center, and his wife, an employe of the Department of Housing and Urban Development, had moved into their newly renovated town house just three months before the shooting. They were the only white couple in an almost entirely black neighborhood and some of their black neighbors, who were upset by the shooting, said afterward that they believed the Flooks had been victimized simply because they were white.

But Marilyn Flook and most of the neighborhood disputed this. Almost all of the residents on the block rallied to the young woman's support in the days following the shooting and attempted to persuade her to continue living there.

Police said last night, however, that she left the house on their advice while they investigated the case and has been living with friends here and her family in Kansas.

On the night of the shooting, Marilyn Flook said, she was awakened about 9:30 p.m. by the insistent ringing of the front door bell. After about 10 minutes, the ringing had become irritating, so she went downstairs to see who was at the door.

As she reached the bottom of the stairs, she remembered, she heard her husband shout from an upstairs bedroom, "Don't open the door."

The woman said however, that when she looked through the front bay window and saw a male figure outside, she mistook him for the paper boy and began to open the door. As she unlocked the dead bolt latch, two men began shoving against the door. She pushed back with all her might, screaming for help from her husband.

She had almost gotten the door shut, she said, when her husband came running down the stairs. Just then, one of the men reached around the open door and fired one shot from a handgun. The bullet struck Frank Flook in the forehead and he died almost instantly.

The two men, who had never said a word during the incident, fled immediately.

Police said they were continuing to search for a second suspect in the case.