Agra: A 45-year-old lower division clerk of Aligarh Muslim University (AMU) was arrested on Monday for allegedly sending extortion letters in gangster Lawrence Bishnoi's name to at least eight residents of Aligarh and demanding around Rs 2 crore in cryptocurrency, police said.The case surfaced on June 6 after a doctor and a jeweller approached Aligarh SSP Neeraj Kumar Jadaun, claiming they had received threatening letters through post. The letters demanded 50,000 USD, equivalent to about Rs 50 lakh, and warned of dire consequences if the amount was not paid.During the investigation, police found that similar letters had been sent on June 3 from the General Post Office (GPO) in Connaught Place, Delhi, to eight prominent individuals in Aligarh. A special team was formed to investigate the case in coordination with the postal department. Police teams travelled to Delhi, examined CCTV footage, checked hotel records and sought assistance from Delhi Police.After analysing CCTV footage from the post office and using technical surveillance, investigators identified the suspect as Hasmat Hussain and arrested him from the Civil Lines area. Officers recovered the T-shirt and sling bag allegedly used while posting the letters, along with a fake Aadhaar card."All eight recipients were connected to AMU and included professors, doctors, alumni and a member of the Old Boys' Association. The accused worked at the university and knew all the recipients. He was aware of their financial status and properties, which he allegedly used as the basis for the extortion demands," SSP Jadaun said.Following the complaints, six FIRs were registered at Civil Lines police station under Section 308(2) (extortion) of the BNS. Police said Hussain told investigators that he traded in Bitcoin and other cryptocurrencies and had travelled to Delhi to post the letters. Investigators also recovered a mobile phone that allegedly showed cryptocurrency trading activity. Police suspect he used the fake Aadhaar card while travelling and staying in hotels to conceal his identity.