An officer of US security agency FBI will assist and participate in the probe related to the multi-crore call centre scam. An officer from Federal Bureau of Investigation arrived in Thane on Friday and exchanged information gathered by both the sides about the scam in which US citizens lost millions of dollars. The FBI officer is also likely to question those arrested in connection with the scam in the next couple of days. <br/><br/>Joint Commissioner of Police Ashutosh Dumbre said FBI has appreciated Thane Police for uncovering the scam. While 71 people have been arrested so far, a look out circular to nab Sagar Dharmesh Thakkar, the alleged mastermind of the scam has been issued. More than a dozen call centres were involved in this scam where executives posed as US tax authorities and duped a large number of American citizens. Police unearthed the scam, involving more than 500 crore rupees, after raiding seven call centres in Mira Road.