"Mr. Tabatabai's shot!" the dark-haired young man blurted out in broken English, his left leg bleeding, as he banged on the sliding-glass door of the two-story brick Bethesda home.

Inside, a terrified teen-aged girl looked up from the television show, "Loveboat," and slid open the door.

Shawn Tabatabai, his left trouser leg rolled up to expose a gashed and bleeding shin, hobbled into the richly decorated living room leaving a track of blood through the house. He climbed the stairs to the master bedroom and called the police.

Minutes earlier, the man's cousin, Ali Akbar Tabatabai, a leading opponent of Ayatollah Ruhollah Khomeini, had been fatally shot -- terrorism had come to a quiet Bethesda neighborhood.

Stretching out for several blocks off Greentree Road, the neighborhood comprises contemporary, two-story homes whose prices average about $250,000.

Tabatabai had lived there for two years, keeping a distance from most of his neighbors, rarely seen outside the brick and wood home where he was killed.

"He was a bachelor in a neighborhood of families. He didn't have children, he didn't have animals, he didn't work out in the yard. We had very little in common," one of his neighbors said yesterday.

But Tabatabai did cultivate a friendship with one family, Dr. Murray Kirshner, a dentist, and his wife and children who lived next door.The Kirshners said Tabatabai's home was expensively furnished and decorated with his own art work.

The Kirshners said Tabatabai expressed fear to them, as he had to other neighbors, about his own safety Dr. Kirshner said Tabatabai told him he frequently had secret meetings in shopping centers, but recently felt safer in his own home.

Ever since the shah was overthrown, neighbors had joked in black comic fashion, that the aloof Tabatabai might be targeted for attack by antishah forces.

"A friend of mine said I should put a big purple arrow on my garage, pointing toward his house and saying, 'The Milks live here, Tabatabai lives over there,'" said Leslie Milk, who lives behind Tabatabai.

Tabatabai seemed increasingly worried about his own safety in the aftermath of the Iranian revolution and the ascendency of Ayatollah Khomeini, neighbors said.

He directed neighborhood children not to use the public sidewalk running behind his house. He started keeping his shades and curtains tightly drawn round the clock. He had a burglar alarm system installed and tested it repeatedly, letting it blare throughout the neighborhood. He called Montgomery County police several times to report threats on his life. Police said they made numerous trips to inspect the house.

But neighbors said none of this seemed particularly frightening until yesterday, when even mundane happenings began to come under the scrutiny of swarms of police and FBI agents probing the assassination of their neighbor.

On nearby Fernwood Road, police found an abandoned U.S. Postal Service delivery truck, believed to have been driven by Tabatabai's assassin. s

Michael Kirshner, 15, one of Tabatabai's next-door neighbors, recalled seeing a man driving such a jeep-type mail truck toward Tabatabai's house about 11:40 a.m. yesterday. "The mailman had already come, so I thought it was pretty strange to see a mailman coming up the street," Kirshner said.

Police guarded the abandoned red, white and blue truck and dusted it for fingerprints before towing it away.

Meanwhile, curious neighbors flocked to the murder scene to learn more details of the assassination of the man they hardly knew.

The neighbors recalled that in recent days, many expensive cars -- including a Rolls Royce -- had been parked outside the house.

"Some business was obviouly going on in there," one neighbor remarked.

Police cordoned off Tabatabai's property with a yellow plastic ribbon and later swept the rain-soaked rolling lawn with metal detectors looking for bullet casings.

A late afternoon thunderstorm cleared away most of the curiosity seekers, and by early evening the only other evidence that anything was amiss was a broken window and glass littering the ground behind the slain man's home. w

It was from that window that the young man had fled from Tabatabai's house to the home about 50 feet away where the teen-aged girl let him use the telephone.

The girl and her family were later besieged by police and reporters, who upset what was to have been a full day of house cleaning. "This was the day I'd set aside to do all the housework that I hadn't gotten done," the girl's mother said.