JERUSALEM — The death of a popular activist while in the custody of the Palestinian Authority on Thursday has infuriated Palestinians across the West Bank, set off a large protest in Ramallah and put a spotlight on a recent crackdown on the authorities’ opponents.
The activist, Nizar Banat, 42, was known for his fierce online criticism of the authority, the Palestinian government that exercises limited self-autonomy in parts of the West Bank. His family says he was fatally beaten by Palestinian security forces.
The authority has not given a full accounting of what happened but said his health “deteriorated” during his arrest and has promised an investigation.
An investigative committee will be given all the information it needs to “enable it to proceed with its work” and to “expedite the process of exposing the truth,” said Mohammed Shtayyeh, the prime minister of the authority.
The authority, facing sharp criticism over the cancellation of national elections and a resurgence of popularity for its rival, Hamas, has recently arrested dozens of its opponents around the occupied West Bank.
Mr. Banat’s death, coming during that push, has posed a new crisis for the authority, whose standing has plummeted in the past couple of months as it canceled what would have been the first legislative and presidential elections in 15 years and watched Hamas’s popularity take off last month when it attacked Israel with rockets. Mr. Banat had been a candidate in those parliamentary elections.
His death highlighted the growing chasm between senior Palestinian officials — many of whom live in expensive homes, benefit from special Israeli permits and often express unquestioned fealty to Mahmoud Abbas, the authority’s president — and the broader Palestinian public, which bears the brunt of the Israeli occupation.
Palestinians across the West Bank have increasingly expressed frustration with what they describe as their government’s oppressive and authoritarian tactics aimed at quashing freedom of speech.
“It is clear that we live under a corrupt system that is waging war against anyone who criticizes it,” said Ammar Banat, 27, a cousin of Nizar Banat. “Suffice it to say that we are not only living under an Israeli occupation but a Palestinian one, too.”
Nizar Banat was a house painter, but had a following online for his acerbic commentary, including criticism of the authority’s relations with Israel. From his home in Dura, a village south of Hebron in the West Bank, he would post comments that few would dare to make but that often resonated with the broader public.
Ammar Banat and other family members said a large contingent of security officers forced its way into a home where Mr. Banat was staying in central Hebron early Thursday. He had been living there, in an Israeli-controlled part of the city, for much of the past seven weeks after his home in Dura was shot at, his cousin said.
The relatives said the Palestinian forces beat him viciously, doused him with pepper spray, insulted him and dragged him on the ground.
Hours later, after calling friends in the security services to check up on Mr. Banat’s condition and looking for him at local hospitals, the family learned that he was dead, Ammar Banat said. Nizar Banat had been in “excellent heath,” his cousin added.
The Palestinian Authority has not released a detailed account of what caused Mr. Banat’s death, and declined to answer questions.
On Thursday evening, Ammar Al-Dwaik, the director of the Independent Commission for Human Rights, said at a news conference that two doctors at an autopsy called it “an unnatural death,” with bruises and abrasions on many areas of his body, including the head and neck.
Jibrin al-Bakri, the Palestinian governor in the Hebron region, said in a short statement that Mr. Banat’s health had “deteriorated” during his arrest. He said Mr. Banat was immediately transferred to a hospital, where doctors determined he was dead.
The U.S. State Department weighed in on Mr. Banat’s death on Thursday evening. “We are deeply disturbed by the death of Palestinian activist Nizar Banat and the information that has been reported regarding the circumstances of his death,” the State Department spokesman, Ned Price, said in a statement. He urged a “thorough and transparent investigation” and said the United States had “serious concerns about Palestinian Authority restrictions on the exercise of freedom of expression by Palestinians and harassment of civil society activists and organizations.”
Mr. Banat frequently posted videos on his Facebook page in which he would criticize the administration and policies of officials like Mr. Shtayyeh.
This week, he lashed out at the Palestinian Authority for making a deal with Israel to acquire vaccines, some of which were nearing their expiration date. The authority ultimately rejected the deal.
In late April, he blasted Mr. Abbas for declaring he would only allow parliamentary and presidential elections to take place if Israel approved allowing voting in East Jerusalem.
“You want to punish Israel by depriving the Palestinian people of elections,” Mr. Banat said. “What kind of stupidity is this?”
In addition to criticizing the authority, Mr. Banat would take aim at Israel; at Mohammed Dahlan, an exiled rival of Mr. Abbas; and the L.G.B.T. community.
Mr. Banat’s death came amid a broad arrest campaign by the authority in which at least 50 people have been arrested over their political activities, said Muhannad Karaja, the director of Lawyers for Justice, a legal aid group.
The authority has moved to suppress Palestinian critics, Mr. Karaja said, because it feels particularly “weak” in the wake of its decision to cancel the elections and “marginalized” by the recent increase in Hamas’s popularity.
Some have put the count of those detained at a significantly higher number. Dimitri Diliani, a Fatah member allied with Mr. Dahlan, said the authority has detained 170 activists associated with Mr. Dahlan since late May, when Secretary of State Antony J. Blinken visited Ramallah.
“Blinken’s visit gave a boost to an isolated president,” Mr. Diliani said, referring to Mr. Abbas. “Blinken’s visit made them feel strong enough to commit atrocities.”
At the protests on Thursday afternoon in Ramallah, security forces blocked some streets in the city, tried to disperse crowds by firing tear gas and hit at least one man with wooden batons. People chanted for the “fall of the regime” and said “Get out, get out, Abbas.”
Hamas, the militant group that controls the Gaza Strip, condemned what it called Mr. Banat’s “assassination” and said it amounted to an “organized and planned crime that reflects the intentions and behavior of Abbas’s authority and his security services toward our people and opposition activists.”
Ammar Banat said his cousin had recently received a series of threats from Fatah and Palestinian Authority security officials in the Hebron area.
“They were set on taking him out,” he said. “I have no doubt that they wanted to kill him.”
Isabel Kershner contributed reporting.