FULA, Israel, Sept. 25 - Something about the tall thin man waiting at the bus stop struck Rami Mahamid as suspicious. There was all that dust on his shoes and then there was that big black duffle bag in his hand.

He was a fellow Arab. But Rami, who is 17 and Israeli, thought the stranger was Palestinian, and feared he was a suicide bomber.

What happened next illuminates the problems faced by Israel's Arab minority, accounting for nearly 20 percent of the population of 6.6 million. It may also, perhaps, supply proof that Jews and Arabs can live together here, along with evidence of the suspicions that drive them apart.

Rami saved an untold number of Israelis by alerting the police. But he was wounded after he stepped in, and he later found himself bound in a hospital, suspected by the Israeli police and the internal intelligence service of being the bomber's accomplice. They kept him shackled for two days after he was lucid enough to explain what happened, he said. Other Israeli Arabs, after all, had helped Palestinian terrorists.

But Rami foiled one. There were just the two of them last Wednesday at the bus stop by an Israeli Arab town, Umm el-Fahm, so Rami politely asked to borrow the man's cellular telephone. He walked a few feet away and dialed 1-0-0 Ñ the Israeli police. Speaking softly, he shared his suspicions.

Then Rami walked back, returned the telephone, and sat down beside the stranger, giving nothing away.

"I felt I did what I was supposed to do," Rami said today, seemingly puzzled by the suggestion that he might have simply walked away, or run, from the whole matter.

A policeman, Moshe Hizkiya, arrived with his partner in time to prevent the next bus from stopping for the waiting men, the police said. When the policemen demanded to examine the man's bag, it exploded, killing Mr. Hizkiya and the bomber. Rami had edged away, but not far enough.

He was conscious of a horrible blast, of body parts around him, of searing pain. Then he awoke to find himself in Ha Emek Hospital here, badly wounded and under guard, shackled to his bed.

"They didn't believe me," he said as he lay in the same bed today. "I felt harmed, and very angry."

A slash in his throat is sealed with 10 staples. His broken left arm is in a cast, and his fractured left leg is in traction. The shrapnel has been removed from his liver. A lean youth with close-cropped black hair, he sipped fruit juice through a straw and spoke slowly, with difficulty.

"I wouldn't feel sorry for what I did, even if I lost my life," he said.

Today, the local commanders of the Israeli police interrupted a conversation at Rami's bedside to present him with a certificate. It praised him for "saving life with great courage and initiative" and celebrated his "good citizenship."

For Arabs, citizenship in Israel can be a tormenting affair. Rami, who delivers furniture for a living, took it for granted that his fellow Israeli Arabs would approve of his intervention. But his father, Mahmoud Mahamid, 58, is less certain, though the family does not want to share that view with Rami.

"I think there are people who are criticizing it," Mr. Mahamid said.

Many Israeli Arabs identify themselves as Palestinians; they relish their relative freedom and opportunity as Israelis, but resent their frequent treatment as second-class citizens in a state that defines itself as Jewish. Increasingly, their fellow citizens suspect them of ties to terrorism.

A year ago, an Israeli Arab blew himself up on a train station in northern Israel, killing three other people. In an incident last month that commanded intense attention in Israel, two Israeli-Arab nursing students fled from a bus north of here after a stranger warned one of them that something terrible was about to happen, the police said.

Nine people died minutes later, when the stranger blew himself up. The women have denied knowing of the threat.

Israeli Arabs, like Rami, have also been victims of Palestinian attacks.

Brig. Gen. Dov Lutzky, one of the commanders who presented Rami with his citation today, said that here in northern Israel, with its large Arab population, Israeli Arab passers-by were often first to the scene of a bombing, helping the victims. "I'm not willing to put a title and say `All the Arabs are like this' or `All the Arabs are like that,' " he said. "Rami is the ultimate answer to those who put a general title."

General Lutzky defended the decision to shackle Rami, saying his story was so unusual that it had to be checked thoroughly.

He said he understood Israeli Arabs' sympathy for what he called their Palestinian "brothers and sisters," adding, "The situation of Arabs who are citizens of Israel is very, very complicated."

Rami identified himself as Israeli, not Palestinian. But he spoke with some bitterness about life as an Arab here. "I feel always under suspicion," he said. "You don't feel free in your own country."

Mr. Mahamid described Israeli Arabs as a soccer ball kicked between the conflict's antagonists. Before the 1967 war, he said, he married a Jewish woman, and though the couple separated a few years later, he has two adult children who are Jewish and live in Bat Yam, an Israeli town.

On his Israeli identification card, he had his first name legally changed to Avraham so that, he said, his daughter would not have to say when she married that her father had the obviously Arab name Mahmoud. He stayed away from her wedding. "She grew up in a different way," he said.

From her seat in the middle, Rasheedeh Mahamid, 46, Rami's mother, said she was very proud of her son. "He did what he should do," she said. "He couldn't bear seeing innocent lives lost."

"But that's not enough," she continued. "Arabs and Jews should think of this and achieve peace, understand that violence only breeds violence."

Muhammad Szubi, 40, was also visiting the orthopedic ward at Ha Emek Hospital today. He stopped a reporter and nodded toward Rami's bed. "My nephew was in that same bed last year," he said.

Mr. Szubi, also an Israeli Arab, told a different story of vigilance against suicide bombers, and its price. He said his nephew, Ahmed Szubi, 24, was shot twice in the legs when a police officer stopped his car and mistook the twine spilling from his pocket as evidence of a bomb.

That time, he said, "nobody came to apologize."