A sneaky thief stealing unclaimed cheques from the office of a life insurance company has led to the discovery of a meticulous operation responsible for the loot of at least Rs 15 lakh.

The fraud prevention team of Reliance Nippon Life Insurance Company caught Krishna Roy red-handed and handed him over to Vanrai police recently. Roy had been sneaking into the company's Goregaon East office in the wee hours when security guards would be otherwise occupied and stealing cheques.