Nizar Rayyan, the Hamas military commander who was killed in Thursday's air raid on his home in the Jabalya refugee camp, was a sworn enemy not only of Israel, but also of the Palestinian Authority and its president, Mahmoud Abbas. Rayyan, who had four wives and a dozen children, led the Hamas militiamen who defeated Abbas's security forces in the Gaza Strip in the summer of 2007. He is the third most senior Hamas leader to be killed by Israel, after the targeted killings of Hamas founder Sheikh Ahmed Yassin in March 2004 and his successor, Abdel Aziz Rantisi, a few weeks later. Hamas leaders stressed that Rayyan's death, while a "painful loss" to their movement, would not affect its determination to continue the fight against Israel. A Hamas spokesman said he did not rule out the possibility that the PA had asked Israel to kill Rayyan because of his role in the Hamas-Fatah clashes in 2007. "Sheikh Rayyan was one of the main reasons why many of Abbas's men did not sleep well at night," he said. "They knew that as long as the sheikh was around, they would never be able to return to the Gaza Strip." A few days before Hamas took full control of the Gaza Strip, Rayyan, dressed in military fatigues and carrying a Kalashnikov assault rifle, declared that he and his supporters were planning to hold Friday prayers inside Abbas's presidential compound in Gaza City. Rayyan personally led the Hamas militiamen who seized the compound and PA security installations throughout Gaza. He later boasted that the Strip had been "cleansed" of "traitors" and "CIA agents" - a reference to Abbas and his former security chiefs. A few months later, Rayyan again issued a threat against Abbas. This time he declared that he would soon lead Friday prayers inside Abbas's Mukata compound in Ramallah, an indication of Hamas's intention to extend its control to the West Bank. That was why PA officials in Ramallah Thursday did not shed tears over his departure from the scene. In fact, some of them privately expressed relief, claiming that he was responsible for the killing of scores of Abbas loyalists in the Gaza Strip during the 2007 "coup." Many Palestinians saw the killing of Rayyan, 60, as a severe blow to Hamas and its armed wing, Izzadin Kassam. Some Hamas supporters said on Thursday that Rayyan was more significant than Prime Minister Ismail Haniyeh or senior Hamas leaders Mahmoud Zahar and Said Siam. "He was one of the most popular figures in Hamas," said a Palestinian journalist who knew the slain Hamas leader for nearly two decades. "He was the type of leader who would go out with the fighters to confront Israeli tanks and fire rockets at Israel. He loved wearing the military uniform." Apart from serving as a "spiritual" leader for Hamas's armed wing, Rayyan was also a teacher at the Islamic University in Gaza City. His students referred to him as "The Professor" and described him as a prominent Muslim scholar. One student said Rayyan was Yassin's real successor. Rayyan was a leading authority on the sayings of the prophet Muhammad (Hadith), and the basement of his four-story house had been turned into a library of more than 5,000 books and documents on Islam. After Islamic studies at universities in Saudi Arabia, Jordan and Sudan, he returned to the Gaza Strip and worked as a preacher in several mosques. His fiery sermons and involvement in incitement and terrorism resulted in four years in an Israeli prison. When the PA assumed control over the Gaza Strip in 1994, Rayyan was one of the first Hamas members to find himself in a Palestinian prison, together with Zahar and Rantisi. At the beginning of the second intifada, Rayyan sent one of his sons to carry out a suicide attack in Gush Katif's Elei Sinai in 2001. Two Israelis were killed. Rayyan was also responsible for a series of suicide bombings and attacks inside the Green Line, including the suicide bombing in Ashdod Port in 2004 in which 10 Israelis died. In recent years, Rayyan served as a liaison between the political leadership of Hamas and Izzadin Kassam. He is even said to have been one of the very few Hamas operatives who knew where IDF soldier St.-Sgt. Gilad Schalit was being held in the Gaza Strip.