JENIN, West Bank (Reuters) - Discovering his mobile telephone franchise burgled, Abu Sameh sought justice -- not at the tank-battered Palestinian police station of his home town Jenin but in the grim alleyways of its refugee camp.

He secured an audience with Zekariya Zubeidi, chief of the militant al-Aqsa Martyrs Brigades in the West Bank and a fugitive from Israeli special forces. Zubeidi promised to track down the thieves who had almost ruined the businessman.

"Twenty-four hours later the police called to say two men had been caught and my phones returned," recalled Abu Sameh after the Brigades handed them over.

A bigger surprise followed when one of the thieves became a Zubeidi lieutenant. Scouring Jenin for criminals by day and attacking Israeli troops and Jewish settlers by night, he was the latest strange hybrid born of three years of Middle East chaos.

"When we catch a crook, we let him off with a warning that next time he'll get hurt. And then we try to recruit him," Zubeidi told Reuters. "Tough times call for tough tactics."

Israeli crackdowns on a Palestinian revolt have devastated the government infrastructure of the West Bank and Gaza Strip, swelling the ranks of militant groups like the Brigades. Their fight against Israel enjoys broad support among ordinary Palestinians -- less so their assumed law-enforcement role.

"These guys are felons who committed theft, arms sales, and extortion, and were untouchable once they joined the Brigades," said Bassem Eid, director of Palestinian Human Rights Watch, which monitors human rights abuses by both Israel and the Palestinian Authority.

Noting that the Brigades had killed at least seven Jenin residents suspected of collaborating with Israeli intelligence, Eid added: "Their power as 'police' is a function of fear."

IF YOU CAN'T BEAT THEM...

Palestinian security services have kept a low profile since Israel reoccupied much of the West Bank last year following a series of suicide bombings. Several police stations have come under Israeli attack. Armed policemen risk being shot on sight.

In Jenin, the presence of the security services is limited to traffic police who wear fluorescent vests and carry no weapons in a bid to avoid being mistaken for militants by Israeli snipers.

"In the absence of law and order, which is mainly caused by the Israeli occupation forces' destruction of our compound and jail, we are paralysed," said a Jenin police officer who did not wish to be named. "We cannot take any action against criminals."

Alik Ron a former chief of Israeli police in the West Bank, agreed that Palestinian forces were powerless, but blamed their inaction.

"They did not fight terrorism as required by Oslo," said Ron, referring to the 1993 interim deals that won the Palestinians limited self-rule. "Israel had to do the job, and damage to their institutions was inevitable. Now the chaos on the Palestinian street is a problem both sides have to deal with."

Zubeidi says that several Jenin police officers double as gunmen in his group. The Brigades are backed by Palestinian President Yasser Arafat's Fatah and the faction stipend is a welcome supplement to police wages.

Eid said moonlighting by Palestinian security services was common wherever the Brigades hold sway in the occupied territories. The link has prompted Israel to shun Arafat for fomenting violence. He denies it.

LIEUTENANTS AND DEPUTIES

Zubeidi and his lieutenants move about Jenin openly, communicating by cellphone and making no attempt to conceal their weapons. The sight causes little fuss in the refugee camp, which survived a punishing Israeli sweep in April 2002. Townspeople are more easily flustered.

"These guys fight the Israeli occupation, and that's important," said a Jenin resident. "As for them acting as police -- that's a cause I don't believe in."

Zubeidi attributed the Brigades' relative popularity to the Fatah connection, setting them apart from the Jenin chapters of rival militant groups Hamas and Islamic Jihad.

As for his conspicuousness -- rare for someone topping Israel's most-wanted list -- Zubeidi credited a network of lookouts which, he said, extended the Brigades' dual role.

"We have around 300 youngsters that we 'deputised' to keep a lookout all over town. They phone us the moment there is an Israeli incursion or a crime under way," he said.

In either case, the Brigades' response is similar. "A few armed members of the group rush to the site and open fire," Zubeidi said. "If it's a thief, he won't fire back -- they don't have guns. If it's the army, it will, and then we fight it out."

For Hamza, the burglar-turned-militant, joining the Brigades was a form of salvation. "I search for other thieves in order to recruit them," he said. "This is the right path and I thank God for showing it to me.

At 29, Zubeidi does not share his zeal, holding no hope for a bona fide police position should he live to see peace. "If we get a state of our own, I want to retire, to rest," he said.