A day after announcing the establishment of his own political party, billionaire Russian Oligarch Arkady Gaidamak was questioned by police under warning for close to 10 hours on Monday regarding suspicions he took part in a massive Bank Hapoalim money laundering scheme. In March, police froze close to $400 million deposited in Bank Hapoalim's branch 535 on Rehov Hayarkon in Tel Aviv. Police suspected that the money which belonged to 200 of the bank's international clients was obtained illegally and had been knowingly laundered by bank employees. Gaidamak was detained by investigators from the police's Serious and International Crimes Unit at 3 AM Monday as he made his way to Ben Gurion Airport for a trip to Russia following his Betar Jerusalem soccer team's 3:2 victory over rival Ben Yehuda. Police decided to arrest Gaidamak after a key witness who assisted the 53-year-old billionaire in running his Bank Hapoalim accounts arrived in Israel on Sunday. Police accompanied Gaidamak to his Caesarea home that was thoroughly searched. Gaidamak was released from police custody after posting NIS 1 million in bail. Police also confiscated his passport and forbid him from leaving the country. Examining Gaidamak's bank accounts at the Hayarkon Branch, police discovered close to $50 million that was surprisingly withdrawn just before police raided the Tel Aviv branch in March. Police are also investigating whether Gaidamak was tipped off about the imminent raid by one of the officers involved in the investigation. Police said that the second person questioned together with Gaidamak - Nahum Galmor - allegedly assisted the Russian businessman in running his Bank Hapoalim accounts and was therefore intimately familiar with his dealings. Following the interrogation Gaidamak said he was happy to be given the opportunity to present his version. He added his hope that his part in the affair would be fully clarified and that now he could return to his public and social activities . "The police asked me to come in and give explanations about my businesses," Gaidamak told reporters during a press conference he convened Monday afternoon in Ramat Gan. The Russian businessman accused the police of persecuting him claiming that had he not been a rich Russian or the owner of a soccer team he never would have been questioned. In March, following a yearlong investigation, police detained 22 employees from Bank Hapoalim's branch on Rehov Hayarkon suspected of crafting and implementing two methods used by local and foreign businessmen to launder illegally-obtained funds. Using the "back-to-back" method, police said, businessmen would transfer large amounts of money into accounts belonging to straw companies they fictitiously owned and would transfer the money back abroad several minutes later after it was cleaned of its illegal origins. In some cases, police said, the bank would grant the businessmen loans matching the amount of money deposited in the Hapoalim account and the businessmen would then transfer the "clean" loan overseas while the "dirty" money was swallowed up by the bank. Two weeks ago Israel's Ambassador to England Zvi Hefetz was questioned regarding his involvement in the money-laundering scheme. Hefetz was questioned due to his close ties with Russian businessman and Ma'ariv newspaper shareholder Vladimir Gusinsky who had been named as a suspect in the case. Police suspect that Hefetz who served as Gusinsky's representative in Israel before taking up the diplomatic post in London, was aware and even possibly behind suspicious money transfers made into the Russian businessman's accounts at the bank's branch on Rehov Hayarkon.