Five gunmen on Sunday shot and killed an alleged "collaborator" in front of hundreds of people in a public square in the West Bank refugee camp of Jenin, accusing him of giving information to Israeli authorities, witnesses said. The gunmen, who identified themselves as members of the violent Islamic Jihad group, accused the victim of helping Israel killed two militants last week in a targeted attack, said witnesses and Islamic Jihad members. Sunday's killing came in response to an Israeli helicopter attack on the homes of the two militants last Wednesday, said an Islamic Jihad official. The victim was identified as Bassem Malah, 22, who worked in the Israeli Arab town of Umm al Fahm. He was due to be married next week. Islamic Jihad said he also worked for the Israeli security services. About 500 people were in the square when the unmasked gunmen fired into Malah's chest. Some were chanting "Allahu Akhbar," or God is Great, and anti-Israel slogans, witnesses said. After the killing, some bystanders put shoes on the head of the corpse, as a sign of disgrace, they said.