(By Paul Virgo) Rome, April 16 - Italian prosecutors seized 1.8 billion euros of assets held by Nomura on Tuesday and said they had put the Japanese bank's former chief executive in Europe, the Middle East and Africa under investigation in relation to a probe into a financial scandal at Monte dei Paschi di Siena (MPS). Nomura was involved in one of a series of suspect derivative and structured-finance deals that left a hole of around 720 million euros in the balance sheet of Italy's third-biggest lender. Prosecutors said Sadeq Sayeed, the former head of Nomura International plc, was being probed along with another manager from the Japanese investment bank, Raffaele Ricci. The prosecutors said the Nomura seizure regarded 88 million euros of hidden commissions received by Nomura and 1.7 billion euros of funds deposited with Nomura by MPS by way of collateral for a loan. They stressed that the individuals were under investigation but the Japanese bank as an institution was not. Judicial sources said that the validity of the so-called Alexandria derivatives contract MPS has with Nomura has been suspended. Around 14 million euros belonging to former MPS chairman Giuseppe Mussari, former general manager Antonio Vigni and former finance chief Gianluca Baldassarri were seized on Tuesday too. Sayeed, Ricci, Mussari, Vigni and Baldassarri are being probed for crimes including usury, aggravated fraud, obstructing banking watchdogs and issuing false statements. Mussari last year resigned from MPS and stepped down from his subsequent post as chairman of the banking association ABI after the scandal exploded in January. Baldassarri is under house arrest. Police and prosecutors investigating the MPS scandal were at the offices of the Bank of Italy for "activities linked to the investigation" on Tuesday. Bank of Italy officials are not implicated in the probe but are cooperating with investigators. "The presence of finance police in the headquarters is connected to the collaboration provided for some time to the judicial authorities in relation to investigations into obstructing regulatory authorities, in which the Bank of Italy is the injured party," read a Bank of Italy statement. There are also suspicions senior MPS managers were involved in reports of bribes and corruption regarding the nine-billion-euro acquisition of rival bank Antonveneta in 2008. David Rossi, MPS's communications chief, committed suicide last month by throwing himself out of a window at the bank's headquarters in Tuscany. He was not being probed. MPS, which is the world's oldest bank still doing business, revealed losses of more than three billion euros last year. Before the derivatives scandal broke, the Italian government had approved a 3.9-billion-euro bailout loan to the troubled bank, which may be converted into equity if the bank cannot make its payments to the State.