JERUSALEM — It was a rare phenomenon: A Palestinian civil rights activist appeared on Israel Television and strongly condemned the mistreatment of Palestinian citizens.

What made his televised appearance noteworthy was that Bassem Id, a Palestinian who has worked for the Israeli civil rights organization B'Tselem, was not attacking the Israeli security agencies.

His barbs were directed at the security service of the Palestinian Authority, in whose prison cells a man was tortured to death.

The victim, Mahmoud Jemayel, an activist of the previously pro-Arafat Fatah Hawks, was last seen alive July 26 at a prison operated by the Palestinian Authority in the West Bank town of Nablus.

Three days later, he was brought to a hospital in Jerusalem. Suffering from serious head wounds, Jemayel was in a coma. A day later he died.

His death sparked new signs of growing anti-Arafat sentiment: Large, violent demonstrations in two West Bank towns administered by the Palestinian Authority, an embarrassing hunger strike launched by two prisoners in a Palestinian jail, a Hamas leaflet urging another uprising — this time against the Palestinian Authority.

These events represent one of the biggest challenges to Arafat since the start of self-rule two years ago, and raise serious questions about Arafat's ability to remain in power — and about the future of the peace process itself.

Long before the threat of an intifada was issued, there have been complaints from Palestinians that Arafat's regime was undemocratic, repressive, brutal.

But Jemayel's death was not only an indication of the brutality of the Palestinian security forces.

It was also an example of how far former supporters of Arafat have drifted away from him because of their disillusion with the peace process.

The Fatah Hawks used to operate as pro-Arafat vigilantes in the winding alleys of the Nablus casbah, enforcing the directives of the Palestine Liberation Organization and orchestrating the intifada against the Israelis.

But in the two years since the establishment of the Palestinian Authority, members of the Fatah Hawks — as well as other Palestinians with high hopes for self-rule — have grown disenchanted with Arafat.

"The situation is particularly frustrating because the expectations were so high," a respected Palestinian civil rights activist who asked to remain anonymous said in an interview.

"We thought we were getting a Palestinian democracy, and yet we received another Arab authoritarian and corrupt regime."

News of Jemayel's death prompted a violent protest Aug. 1 in Nablus that ended with Palestinian police fatally shooting a demonstrator.

And for the first time in the relatively short history of the Palestinian Authority, anti-Arafat sentiment erupted throughout the Palestinian community.

Leaders of Israel's Arab population condemned the brutality of the Palestinian security forces; Id appeared on television demanding an investigation. Arafat tried to show that he was responding: Three Palestinian security officers were convicted in the death of Jemayel after a court martial in the West Bank town of Jericho.

Gen. Amin al-Hindi, the head of Palestinian intelligence, insisted this week there were only rare instances of prisoners being tortured and that measures were being taken to ensure that they did not recur.

But inter-Palestinian tensions grew. On Friday of last week, two Hamas members jailed in the West Bank town of Tulkarm were hospitalized after a weeklong hunger strike.

Soon after Friday prayers, riots erupted in Tulkarm, where some 2,000 protesters voiced solidarity with the hunger strikers. The demonstrators threw stones at the police — Palestinian, not Israeli — who responded with gunfire.

The riots ended with the death of a Palestinian father of two and the wounding of seven others.

Days after the riot, an intifada was threatened, on a leaflet issued in the name of Hamas. Not coincidentally, the Palestinian Authority blamed armed Hamas members for the fatal shooting.

The leaflet contained a simple and direct call to arms. "To respond to the crime of the authority in Tulkarm, our people should rise up against this collaborating authority.

"Arafat's authority has tried — through repression of freedom, assassination, arrest campaigns and choking free opinion — to force us to accept weak agreements that are broken by the Zionists every day," the leaflet said.

Hamas leaders in the Gaza Strip and West Bank distanced themselves from the leaflet, but it has left a nagging question: Is Arafat in control?

Arafat has been caught between Israeli pressure to destroy Hamas' infrastructure and growing Palestinian animosity. Putting more Hamas activists behind bars may mean better relations with Israel — but the situation at home worsens.

A senior Israeli intelligence source was quoted this week as saying that "more and more people support Hamas, and the status of Arafat has been eroded."

The source did not believe that Arafat's fall is around the corner. But, the source added, if the Palestinians are effectively controlled by opponents of the self-rule accords, then Israel may be forced to freeze the peace process.

Hamas has not yet repeated the bloody terror attacks of February and March, but experts such as Yigal Karmon, an anti-terror adviser for the previous Labor government, believe that may soon change.

Karmon said this week that Hamas' suspension of terrorism was only a temporary strategy to speed up the Israeli military redeployment from Hebron.

Now Karmon said it was only a matter of time — three months, in his estimate — before Hamas resumes attacks, this time in Jerusalem.

Israeli security officials have praised the Palestinian Authority for its efforts to suppress Hamas. But others criticize Arafat, citing his failure to disarm Hamas and other militant groups.

Arafat has managed so far to maneuver between Palestinian radicals and the Israelis, but he may soon have to choose.

If Hamas continues to loosen Arafat's grip, he may need Israel's help to maintain his rule.