An unsigned letter in the name of former Mumbai police commissioner Param Bir Singh and addressed to Maharashtra chief minister Uddhav Thackeray is being verified, a statement from the chief minister’s office said.

The letter, which was emailed to the chief minister’s secretariat in the afternoon, accuses home minister Anil Deshmukh of corruption.

The home department is trying to contact Singh and the sender’s email address is being verified because Singh’s email address in official records was different, it added.