Jerusalem - Police questioned Israeli Prime Minister Benjamin Netanyahu on Thursday for the second time over allegations that he improperly accepted gifts from wealthy supporters, pressing ahead with a probe that has threatened to challenge his long leadership of Israel's government. Netanyahu has adamantly denied wrongdoing.Police said investigators went to Netanyahu's official residence in Jerusalem in a case that local media say arose from allegations involving high-profile figures in international business and Hollywood.Police said investigators questioned Netanyahu for five hours about suspicions that he "allegedly received benefits" as well as about another undisclosed affair. His questioning on Monday lasted more than three hours.Few details of the allegations against Netanyahu have been officially released, with Israel's Justice Ministry revealing only that the prime minister was being questioned "on suspicion of receiving benefits from business people".SuspicionsBut Israeli media have reported that Netanyahu accepted "favours" from businessmen in Israel and abroad, allegedly including billionaire Ronald Lauder and Hollywood producer Arnon Milchan.Israeli Channel 2 TV has said Netanyahu is the central suspect in a second investigation that also involves family members.Netanyahu has repeatedly denied wrongdoing, portraying the accusations as a witch hunt against him and his family by a hostile media opposed to his hard-line political views.He has pointed to previous suspicions raised against him, none of which resulted in any criminal proceedings, as a sign that he has done nothing wrong in this most recent allegation as well. "There won't be anything because there is nothing," Netanyahu has said frequently.Serving his third consecutive term with a stable coalition government, Netanyahu is on track to become Israel's longest-serving leader, should he complete his full term in office in 2019. He does not appear to have any serious foreseeable challenger to his rule.While the probe is still in its infancy, a mounting investigation could put pressure on Netanyahu to step down.His predecessor, Ehud Olmert, did so in 2008 just months before he was formally indicted on corruption-related charges. Olmert is now serving a prison sentence after being convicted of accepting bribes.After eight years in office, in addition to an earlier term in the 1990s, Netanyahu has garnered a reputation as a cognac-swilling, cigar-puffing socialite who is as comfortable rubbing shoulders with international celebrities as he is making deals in parliament.Scandals have dogged him and his wife, Sara, over their lavish tastes.They have been chided for excessive spending on anything from pistachio ice cream to scented candles to ringing up $127 000 in public funds for a special sleeping cabin for a five-hour flight to London.