The leader of the Hizbullah guerrillas said Wednesday that he believed IAF avigator Ron Arad, who disappeared after his plane was shot down over Lebanon in 1986, is dead. But Sheik Hassan Nasrallah, whose guerrillas fought Israeli forces for 18 years in southern Lebanon and has engaged in several previous prisoner exchanges with Israel, said he did not base his conviction on facts but rather on calculations. "My deduction is two words: 'dead and lost,'" he said in an interview on the local New TV station. It was the first time Hizbullah so explicitly explained the possibilities of Arad's disappearance because finding him or news about him would have been a prize for the guerrillas. Eliad Shraga, the lawyer for Arad's family, told Army Radio that Nasrallah had no relevant information about Arad. "When it was it was comfortable for him, he said he was alive, when it was comfortable for him, he said he had information on Ron's whereabouts," Shraga said. "He is the master of manipulation." Former Shin Bet head Avi Dichter dismissed the Hizbullah leader's comments as well, saying that as far as Israel knows, Arad is still alive. He noted in an interview with Army Radio that Nasrallah is not an independent man, rather "a finger on the hand of Iran." Israel and Hizbullah have held sporadic negotiations through German mediators over a prisoner swap that would reveal Arad's fate, but Hizbullah has said it has been unable to find any traces of Arad. "Regretfully if we had tangible information we would have achieved an important (swap) deal," he said referring to Israeli demands for news on Arad in return for additional exchange of Arab prisoners held by Israel. Nasrallah recounted an incident in 1989 when Arad was able to escape from the guerrillas, saying he may have died in the mountainous countryside of southeastern Lebanon in an accident while fleeing. He speculated that no one had discovered his body. Another theory discounting that he was still alive was that no group would continue to hold him for that long without making a financial or political demand, Nasrallah said.