PRAYAGRAJ, Sept. 13 -- Cyber fraudsters extorted Rs.7.32 lakh from a teacher in Prayagraj through a 'digital arrest', while three others were duped of Rs.51.91 lakh in separate investment and service scams, police said. FIRs were registered in this regard at the cyber crime police station on Thursday. Cyber police station in-charge Anil Kumar Verma said all the cases were being probed and the bank accounts in which the money was deposited were under investigation. According to a complaint by Ramchandra, a teacher from Katra, he received a call from one Sunil Dutt Dubey, who introduced himself as a deputy superintendent of police, Delhi. Dubey claimed that a case had been registered against him in New Delhi for uploading an objectionable video on social media. On January 17, Dubey threatened to arrest him, send him to jail and have him dismissed unless he paid money. Ramchandra ended up transferring Rs.7.32 lakh in three instalments. Another teacher, Rajshekhar Shukla of Alopibagh, told police that between early May and June 9, he invested Rs.26.45 lakh in online trading through WhatsApp on the advice of a man who claimed to be a SEBI-certified stock broker. Later, he found the app to be fake....