Rome, February 14 - The former head of the finance department of Monte dei Pasch di Siena (MPS), Gianluca Baldassari, was detained on Thursday as part of an investigation into fraud at the troubled Italian bank. Police said there was a risk the probed manager, who is being investigated for criminal association and aggravated fraud, may try to flee. Siena prosecutors have in previous days ordered the seizure of some 20 million euros in assets which Baldassari - who was arrested in Milan - is accused of having entrusted to two fiduciary companies, Galvani Fiduciaria and Compagnia Fiduciaria Nazionale. According to the investigators, the money was initially held in foreign accounts and subsequently repatriated to Italy under a tax amnesty program. The Siena prosecutors say they are certain that the money, as well as some other 40 million euros seized from Baldassari and other suspects, was obtained illegally. Furthermore, the prosecutors say that the money is proof of illicit operations carried out in the bank by finance department. MPS, Italy's third-largest lender and oldest bank, is creaking under the weight of failed derivatives transactions and a corruption scandal which has involved some of the bank's top managers. The bank was thrown into crisis in January when it emerged that a shady series of derivative and structured finance deals produced losses in excess of 720 million euros.