Economic Offences Wing (EOW) police detained K Ranjith and his wife Priyadharshini, suspected to be the kingpins of the multi-crore FQL cryptocurrency investment scam, from Dindigul on Monday evening. They were taken to Madurai for questioning and are likely to be formally arrested on Tuesday, police said.

At least 40,000 people from Madurai, Virudhunagar, Dindigul and Sivaganga fell victim to the alleged fraud over the past seven months. The couple allegedly operated fraudulent schemes under the names 'FQL Investment Trading', 'FQL Exchange App' and 'VG Investment Group Syndicate'.

Preliminary investigation revealed that agents lured people to invest through cash and UPI transactions. A portion of the funds was allegedly converted into Tether (USDT) and credited to FQL/VG wallets, after which withdrawals failed, according to officials.