Ali Akbar Tabatabai was buried yesterday in a shaded Falls Church grave with a tiny, green copy of the Koran, the prayers of his friends and family and the promise that his crusade against Iran's current ruler would not die with him.

In a brief ceremony at the Islamic Garden, mourners sobbed and quietly chanted Moslem prayers as the casket of the exiled Iranian diplomat, who was murdered Tuesday at his Bethesda home, was lowered into the ground. Daoud Salahuddin, the Washington man charged with the killing, was still at large last night.

The search for Salahuddin took federal agents yesterday to the Iranian Section of the Algerian Consulate, where the suspected killer reportedly had been employed prior to his disappearance.

Federal Bureau of Investigation agents, accompanied by State Department security officers, went to the consulate, located on the second floor of an office building at 2139 Wisconsin Ave. NW. about 10 a.m., and asked for permission to search a suite of rooms.

But Algerian personnel invoked diplomatic immunity and refused to allow the FBI agents and State Department officials to enter the office. The Iranian Interests Section at the Algerian Consulate is the only Washington office of the Tehran government in the absence of diplomatic relations between the United States and Iran.

Tabatabai, who had recently become one of the most vocal opponents of Ayatollah Ruhollah Khomeini, was eulogized in a private service at a Georgetown funeral home before the burial in Falls Church. A colleague called him "a martyr who lost his life on the way to liberty."

The role of martyr is one Tabatabai could hardly have imagined for himself when he first arrived in the United States nearly 30 years ago to pursue an education as an architect. And, in the days since his assassination in the doorway of his Bethesda home, there have been conflicting accounts of just how and why an obscure Iranian civil servant happened to end up in the thick of a violent political struggle that cost him his life.

The fear of violence and talk of politics that had become so much a part of Tabatabai's life in recent months were just as much a part of the funeral.

There were no disruptions as had been feared. Still, women, dressed entirely in black and draped with veils, hid their faces, and men refused to reveal their names. Tabatabai's teen-age daughter did not even attend, remaining at home in another part of the country for safety reasons.

Even as mourners knelt at the graveside, wailing and chanting prayers for the dead, a group of women walked away from the gathering and held an impromptu political talk with reporters that almost overshadowed the service itself.

"Our country is not going to die for nothing, Tabatabai is not going to die for nothing -- those hoodlums will not disperse us," one woman shouted through her tears.

In a promise echoed by many at the services, Tabatabai's twin brother Mohammad vowed the anti-Khomeini demonstration planned for Sunday by his brother's Iran Freedom Foundation would go on as planned.

"No matter how many people they kill," Tabatabai said, his voice quavering, "it will go on."

Yesterday's funeral began in the Georgetown funeral home, where nearly 100 friends and relatives gatherered to hear Tabatabai eulogized in Persian by Mohammad Farzaner, a former embassy official who had worked with Tabatabai during the shah's regime.

A cortege of about 35 cars, escorted by police, then drove past the Islamic Center, on Massachusetts Avenue, where the services originally were to be held. Mohammad Tabatabai later said the plans were changed because of fears of protests at the mosque. Instead, the procession went directly to the Islamic Garden, a Moslem cemetery in the National Memorial Park off Lee Highway, in Falls Church.

There, the casket, draped in green, white and red carnations -- the colors of the Iranian flag -- was carried through black wrought-iron gates to the grave. Under giant oak and maple trees, Mohammad Tabatabai knelt and broke into tears as he threw the first clod of earth over his brother's coffin. b

Minutes later, under a white gazebo a few feet from the grave, Tabatabai spoke in Persian to friends and family.

"I'm hoping today that this sad loss will bring us all together so that we will put aside our trivial differences . . . and work together in unity," he said in a husky whisper.

"It's true that we don't have the muscle to lift a gun and destroy these murderous elements . . . of the Khomeini regime. But we have the power of mind that we can use to get rid of these criminals and free our country."

As Tabatabai was buried in Virginia soil, friends and family tearfully sang the Iranian national anthem. It was a fitting ending for a man who was born in the Iranian town of Hamadan, but who lived his life in two worlds -- that of Iran and America.

When Tabatabai first came to Washington in 1952, he had already earned a law degree from Tehran University but had set his sights on an architectural career. A member of a large, prominent Iranian family and the grandson of a mullah, he enrolled at Howard University's School of Architecture and soon immersed himself in Iranian student politics.

But friends from those days remember that he never quite fit in with the rest of the foreign students on the campus.

"He was more sophisticated than all of us, always the gentlemen." recalls Harry Robinson, a former classmate of Tabatabai who is now dean of the architectural school. "We were all wearing jeans. He was well-dressed, wearing shirts and ties."

Tabatabai was a few years older than the other students and when he took a part-time job at the Iranian Embassy, an Iranian classmate says it made him "a little mysterious. Students were very suspicious of him . . . they considered him secret service for the embassy."

This rumored connection with the Iranian secret service, SAVAK, was to follow Tabatabai throughout his life, even after some celebrated run-ins his friends say he had with the shah's secret police.

There was never any evidence that he was spying for the embassy, according to Khrosro Moradian, another of Tabatabai's Iranian classmates at Howard who today supports the Khomeini government. But the students "isolated" him anyway.

Tabatabai joined the Iranian Student Association, but Moradian said he doubts that he was ever passionately committed to the organization's goal of a democratic Iran.

After Khomeini came to power, Moradian said he was "shocked that he (Tabatabai) had become active, going on radio and television . . . insulting Khomeini. During the shah's regime, he never talked about a democratic Iran . . . That was the time to talk."

Tabatabai's architectural schooling spanned several years before he finally received his bachelor's degree, and another classmate of his in the 1960s defends his low profile in the student unrest of the times.

"Familywise, he didn't have any choice but to be involved with the shah," says Manouchehr Pourhashemi, an architect. "Like the rest of us, he was against the policies in Iran, but it was not popular to attack the political leader."

Pourhashemi, who says Tabatabai used to cook dinner for him and a few friends in their student days, last saw his old classmate in May. He found he "was not the jolly good friend of school time. He had too much on his mind, since the takeover of the Iranian Embassy."

Like scores of other embassy staffers, Tabatabai was tossed out of a job when the shah fled Iran and the supporters of Khomeini took over the embassy here. Immediately, those considered loyal to the old regime were called in, interrogated and, in most cases, ordered back to Iran and almost certain political reprisals.

"There's no doubt he would have been one of the most severely punished," says an ex-embassy official who also lost his job when Khomeini came to power. "He decided to stay, but he tried to intercede for others."

In an interview with The Washington Post shortly after the shah's regime fell. Tabatabai said he had begged Khomeini followers to consider "the human side" of the current unrest.

"Many of these people have served their government for a quarter of a century, they've made a career of being a government employe, and they have served well, they are not extremists," he said.

Tabatabai argued, unsuccessfully, that the career embassy personnel could make a contribution to building Iran. "If these groups are seeking justice, they must also realize our country is falling apart," he said. "It's on the verge of disintegration. It's time not to divide the people but to bring in forgiveness and brotherhood, so that we create a unified front and unite the people to tackle the problems the country is facing."

But when Tabatabai's arguments failed to persuade Khomeini supporters -- and as the violence and political executions back home in Tehran continued -- he sought and was granted political asylum in the United States. Within several months he had helped organize and become the chief spokesman for the Iran Freedom Foundation that was working to topple Khomeini's rule.

Tabatabai, described by those who knew him best as a pro-Western professional who had adapted well to life in America, perhaps sympathized with the plight of displaced government employes because he had been in that situation more than once.

He returned to Iran in 1969 or 1970 to take a job with the military of information. His job was to squire American tourists, reporters and other foreigners around and help answer their questions about Iranian life.

"He was too open, and he wanted to show the bad as well as the good," a close friend says now. "If reporters asked to see a slum, he took them to a slum. Some people thought he was doing this purposely to ruin the government."

By 1972, this friend and others say, Tabatabai had encountered so much difficulty with SAVAK that he was forced to leave the country. Friends say his life was never in danger, only his ability to make a living.

"They kicked him out of the government job, and he couldn't find another job because SAVAK was always after him," a friend says. Tabatabai moved to Italy briefly, then took a job with an architecture firm in Ohio.

Though some Iranians now say Tabatabai came back to the United States to work for SAVAK, others say the shah's secret police harassed him until he left. A third reason given for his leaving Iran, according to one Iranian who was not a friend of Tabatabai, is that he diplomat was involved in an embarrassing incident that offended the Iranian government.

In any case, Tabatabai's fall from favor did not last long. When the shah's ex-brother-in-law, Ardeshir Zahedi, was named ambassador to Washington, mutual friends began to intercede in his behalf. Tabatabai rejoined the embassy staff as a local employe in 1975.

"Zahedi picked him up -- he never paid any attention to the SAVAK report," says a former embassy official. The ambassador also apparently helped Tabatabai settle a back wage dispute in Tehran, giving his new embassy press attache the funds to buy a $149,000 house in Bethesda.

If Tabatabai was seen as a loyal Zahedi lieutenant after that, friends say it was understandable. He worked hard at the embassy and was promoted to press counselor. Still, Tabatabai remained in the background of political events until the embassy fell to Khomeini's supporters and he embarked on the campaign of opposition that ended in a hail of assassin's bullets on Tuesday.