JENIN, West Bank — Relaxing in their rooftop salon one recent night, Amal Qadoura headed to fetch ice cream for herself and her husband when the shooting began. First, she recalled, two bullets were fired at one side of the glass-enclosed porch, followed by a barrage from a hilltop on the other side.

Her husband, Qadoura Moussa, 60, the governor of this region in the northern part of the Palestinian territories, popped a blood-pressure tablet, then grabbed his rifle and headed into the night. He roamed the city for an hour or more before collapsing at a clinic. He suffered two heart attacks and was dead before dawn.

“This person is a coward,” Mrs. Moussa said of whoever fired the shots, between condolence calls Monday afternoon. “But those who sent him were trying to convey a message.”

In the week since his death, Mr. Moussa has been embraced here as a martyr to the Palestinian national struggle, his visage plastered on car windshields and building facades, behind candy kiosks and in front of protest tents. The Palestinian Authority and others close to the governor say he died battling gangs that threatened to bring chaos back to the streets of Jenin, a notorious hub of violent crime during the second intifada reborn in recent years as a model of Palestinian self-rule, cooperation with Israel and economic growth.

“It is a significant setback for the dovish wing of the Palestinian national movement as well as the American and the quartet’s attempt to keep hope afloat in these times when the ‘peace process’ is in tatters,” Prof. Mark Rosenblum, a left-leaning Queens College historian of the Middle East, said by e-mail, referring to the four Middle East peacemakers: the United States, the European Union, Russia and the United Nations. Professor Rosenblum described the “Jenin model” as an important “symbol of a secure and successful de-occupation.”

Brig. Gen. Radi Assidi, commander of the security forces in the region, said people throughout the West Bank “realize that law and order started in Jenin, so any lawlessness that starts in Jenin could spread throughout the West Bank.”

Scores of Palestinians have been detained for questioning in connection with the shooting at Mr. Moussa’s home, officials said, including a number of security officers. While Jenin’s downtown vegetable market bustled with life as usual Monday afternoon, as night fell convoys of heavily armed officers rolled onto the streets and out to a village connected to the leading suspects.

“You can feel the tension and instability,” said Louy Arkawi, owner of Ombashi, a restaurant on one of Jenin’s main thoroughfares. “As a businessman, I want law and order. If there is chaos, my priority will be not to invest more in the city, but to buy weapons to defend myself.”

General Assidi traced the resurging lawlessness back about a year, to the murder of the legendary director of the Freedom Theater, an oasis for decades of so-called cultural resistance. The violence picked up over the past seven or eight months, he said, and escalated in an April confrontation in the nearby village of Bir al Basha between police officers and a man wanted for killing his cousin. The wanted man’s brother fired on the police and ended up dead, General Assidi said, and many here believe that the attack on the governor’s home was retaliation.

“Unfortunately, our leadership in Ramallah heard the bell ringing late,” General Assidi said in an interview at his headquarters here, not yet entirely rebuilt after having been destroyed during the intifada. “We informed them that some members of the security establishment have no loyalty, but nobody paid attention to our request.”

On Monday, General Assidi said, nine of his counterparts from across the West Bank met here with the authority’s top security official, part of a crackdown in which the leadership has vowed to question, arrest and try anyone connected with the attack on Mr. Moussa’s house, the Bir al Basha affair and other recent flare-ups. A new governor, Talal Dwaikat, arrived Sunday, walking the streets for an hour to proclaim his commitment to safety.

“Jenin will not be a place for the gangs,” Mr. Dwaikat told a delegation of Israeli Arab women who came from Nazareth on Monday to express condolences and meet him. “Jenin will be a place of security so we can receive you warmly.”

In an interview afterward, Mr. Dwaikat said he would prosecute every criminal in the region. “There will be no exception,” he said. “Whatever his status in the community or history, law and order is above all of us.

“I want to continue the march of Qadoura Moussa.”

Appointed in 2004 by Yasir Arafat, Mr. Moussa was seen as a man of the street, a humble leader who had served time in Israeli prisons alongside many of his countrymen. Ibrahim Hamadeh, 44, an activist in the governing Fatah Party, recalled that when he was a boy, in a poor family, Mr. Moussa gave him free pens and notebooks from a bookshop he owned.

“He was not a governor; he was a father,” said Mr. Hamadeh, a cook at Mr. Arkawi’s restaurant. “A field-command officer, among the people.”

Mr. Moussa was born in the stone house where he lived at the time of his death. It was built in 1948 atop a steep hill in Marah, a neighborhood of Jenin, and he married on its first floor 31 years ago. He had three sons and a daughter, who gave him three grandsons.

He had bypass surgery 12 years ago. Over the years, he built the house into three stories, and after his death it was packed with mourners.

Mr. Moussa’s favorite spot was the roof: two huge rooms enclosed in glass with 360-degree views that on a clear day stretch to Nazareth and Haifa. He would lounge on the red and black couches, by the window in summer, by the heater in winter, one of his sons said, showing guests his father’s radio, brought from Haifa in 1948; his grandfather’s pocket watch; and a collection of ancient metal teakettles.

Now, the stone of the house and the windows of the porch are pocked with bullet holes.

“I asked him to rest and then tried to help him relax,” Mrs. Moussa recalled of the night of the shooting, May 1. “He walked to his car, opened his car, started the stereo and then went around the city,” she continued, now recounting the story told by her brothers, who accompanied him. “He went to the top hill of Jenin, looked down. He stood there and told them, ‘Look at the city, its shining lights on, and it should remain.’ He was singing along with the radio.”

She waited up. But the call came not from her husband. It was his driver, who took her to the hospital to say goodbye.