Egypt remanded an Israeli spy suspect in custody for 15 days on Saturday despite Israel\'s insistence he was innocent of espionage, judicial sources said. Ilan Grapel, a US-Israeli joint citizen who was arrested in a Cairo hotel on June 12, is to remain in detention for the \"needs of the investigation,\" the two sources said. His initial remand had been due to expire on Monday. Two days after Grapel\'s arrest, Israeli Foreign Minister Avigdor Lieberman strongly denied he was spy. \"I can say categorically that this student, who may have behaved bizarrely and irresponsibly, has no ties with Israeli, American or even lunar intelligence services,\" Lieberman told Israeli army radio. \"This is a mistake or bizarre behaviour on the part of the Egyptian authorities, who have received full explanations from us,\" he added. Egyptian news reports say that Grapel arrived in Egypt on January 25, the same day that mass protests erupted against the three-decade rule of veteran president Hosni Mubarak, and is suspected of having orders to \"sow chaos.\" The official MENA news agency said he \"passed himself off as a foreign correspondent\" covering the 18 straight days of demonstrations that sparked Mubarak\'s overthrow. Egypt was in 1979 the first Arab country to sign a peace treaty with Israel but relations have deteriorated since Mubarak quit in February. On Thursday, Cairo\'s supreme state security court jailed Egyptian businessman Tarek Abdel Razek to 25 years in jail after convicting him of spying for Israel. The court also handed down 25 year jail terms to two Israelis it found guilty in absentia of \"acts of espionage\".