A 36-year-old Southeast man was arrested yesterday at his home and charged with fatally stabbing a Maryland man Christmas Eve night after tailgating the man's car for several blocks in Southeast Washington, D.C. police officials reported.

They said Roy D. Harris of 3421 18th St. SE was charged with murder 1 while armed in the Dec. 24 stabbing of Karlis B. Fitzgerald, 23, of 3001 Branch Ave., Marlow Heights. Harris is an employe of the U.S. Postal Service, police said.

Police officials said information provided to them after a description of Fitzgerald's slayer was broadcast and published last Thursday and Friday led to yesterday's arrest.

"Usually we don't give out descriptions on suspects," a homicide detective said last night. "It was just the particulars of this case."

Detectives said Fitzgerald was driving on South Capitol Street with two companions about 10 p.m. Christmas Eve when a late model Chevrolet Blazer began tailgating his car.

When he stopped his car in the 2900 block of Second Street SE to let off one of his passengers, Fitzgerald and the man who had been tailgating got out of their vehicles, police said.

Without any exchange of words between the two men, Fitzgerald was stabbed once in the chest, police said. One of the passengers in Fitzgerald's car, whose name was not released by police, also was stabbed in the arm during the incident.

The men's assailant then drove away, according to police.

The injured men were taken to Greater Southeast Community Hospital where Fitzgerald died of his wounds about 7 a.m. Christmas Day. The passenger was treated for his injury and released later, police said.

Based on a description provided by the two persons in Fitzgerald's car, homicide investigators released a description and a composite sketch of a heavyset man wearing a blue baseball hat with the name "Harry" or "Harry O" printed on the front in white letters.

The response was almost immediate, investigators said.

"The calls started coming in Thursday and Friday after the story was in the paper," said a homicide detective familiar with the case who asked not to be identified. "I think it was because of the thing with the hat, and that ticked in somebody's brain."

Persons calling with information did not have to give their names. Several callers described a U.S. Postal Service employe who wore a similar hat, police said.

After obtaining a photo of the man named by tipsters, police said they showed it to Fitzgerald's passengers along with the photos of eight other persons.

"There were calls on other suspects, but you have to rule out the good ones from the bad ones," the detective said. "We checked out a few other suspects, but he was the only one that we got more than one call on."

Police said they obtained a warrant from D.C. Superior Court for the arrest of Harris early yesterday and arrested him without incident at his home at about 1:45 p.m.

Harris was being held at the D.C. Central cellblock last night pending arraignment today, police said.