JENIN, West Bank — Palestinian security forces detained a prominent ex-fighter Sunday, stepping up a campaign of arrests following the death of the governor of the northern West Bank district of Jenin, residents said.

Masked security men seized Zakariya Zubeidi in Jenin after halting his car, blindfolding him and shackling him before bundling him into another car and speeding away, residents said.

Zubeidi, who is in his mid-30s, was a well-known militant who once battled Israeli forces before he was granted amnesty four years ago and co-founded a theater. Zubeidi is known in Israel because of his fluent Hebrew and frequent interviews in the Israeli media.

Three residents confirmed his arrest, requesting anonymity because of fear of reprisal.

Palestinian security forces have been rounding up suspects since the governor, Kadoura Mousa, suffered a fatal heart attack earlier this month after gunmen fired outside his home. The residents say Zubeidi was not involved in the shooting incident, but is distantly related to the suspects. His arrest risks enraging his followers.

The Palestinian government has said it believes Mousa's death was caused by the shooting. Officials said Mousa was extremely nervous after the shootout and was hospitalized several hours later because he felt ill.

The new governor, Talal Dwekat, confirmed that forces have been conducting arrests since last week. But he had no comment on Zubeidi.

"We have strong orders to provide security for residents," said Dwekat, who is responsible for security in the Jenin area.

Palestinian security forces have arrested dozens of people following the then-governor's death in early May. Many of them were well-known outlaws, or relatives of the gunmen who opened fire at Mousa's house. The suspects, who include members of local security forces, remain in detention.

Tensions have been high ever since.

During the violent Palestinian uprising against Israel's rule, Jenin was a notoriously lawless place where gunmen roamed freely. Palestinian Authority officials have since battled to restore security.