Rahul Sharma filed a complaint in Parliament Street police station after claiming to receive a call from an unknown person.
Sharma in his complaint quoted the caller as saying, "Don't try to do social service, we have already made it clear to your brother and brother-in-law. This is the last time we are telling you this, next time we will kill you".
"He disconnected the call before I could reply," said Sharma who claims to have recorded the call.
Sharma, who is the founder of Roads Anti-Corruption Organisation (RACO), had filed a complaint on Tuesday against Kejriwal, his late brother-in-law Surender Kumar Bansal, and a public servant, for alleged irregularities in the grant of contracts for roads and sewer lines in Delhi.
Sharma had also submitted a complaint to the ACB for a probe into the alleged "mysterious" death of Bansal.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)