Zakaria Zubaidi, a West Bank militant who laid down his arms in a 2007 amnesty and took up a new role in a theatre, once symbolised the return of order to formerly lawless Jenin.
But his arrest by Palestinian security forces after the death of Jenin's governor is raising the spectre of a resurgence of violence by armed Palestinian groups.
Determined to preserve one of its principal state-building achievements -- applying the rule of law -- the Palestinian Authority has deployed hundreds of security personnel to reinforce the city's lawmen and women.
On Friday, on an official visit to France, Palestinian president Mahmud Abbas called on Israel to allow him to "import arms for the Palestinian police," in a sign of his government's plans to maintain the West Bank's fragile stability.
Dubbed "Jeningrad" by Yasser Arafat, in tribute to stiff resistance by his fighters to a 2002 Israeli army offensive, the city was one of the first in the occupied West Bank to be placed under the control of Palestinian security forces, supervised by US General Keith Dayton and his staff.
But cracks in the new stability, hailed by foreign donors and Israeli military officials, started to show in early May with the sudden death of Jenin governor Qadura Mussa.
Mussa suffered a fatal heart seizure after shots were fired at his home, allegedly by members of a family enraged by authorities' refusal to open an inquiry into the death of a relative during an arrest.
"Weapons must be under control, there can be no weapons outside the law," new governor Talal Dweikat, a general in the intelligence service appointed to the post by Abbas, told AFP.
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Dweikat has launched a crackdown and security sources say that at least 70 people were arrested in Jenin during May. Of those about one third were members of the security forces or militia veterans such as Zubaidi, who was a founding member of the Freedom Theatre, in Jenin refugee camp.
"We will not allow anyone to hide behind the security services, an organisation or a clan," Dweikat said. "Everyone must bear individual responsibility and no one is above the law."
"Jenin has suffered and still suffers from the occupation," he added. "It is the Palestinian citizen who is affected and he has the right to be safe at home. Without security and trust, there can be no education, no success or economic development. There will be a brain-drain and flight of investments."
According to officials and residents, the situation began to deteriorate after the murder in April last year of the Freedom Theatre's Israeli-Palestinian director Juliano Mer-Khamis.
The killing is still unsolved, despite numerous arrests by the Palestinian security services and the Israeli army.
"The Palestinian Authority made a big mistake by its apathy after the assassination of Juliano Mer-Khamis," a Palestinian security source told AFP on condition of anonymity.
"What has happened since in Jenin is the consequence," he said.
The theatre's artistic director, Nabil al-Raee, was arrested by Israeli troops on a raid into Jenin on Wednesday.
Managing director Jonatan Stanczak told AFP that in recent weeks about 10 Palestinian staffers had been summoned to a nearby Israeli army base and interrogated "in a very intimidating and threatening way."
"Usually these interrogations start with 'We know you are the one who killed Juliano, why did you kill him?'"
"They also asked questions about the situation in Jenin in terms of security," Stanczak said, indicating the growing concern of the Israeli army.