The sender has also alleged that the anti-graft crusader has earned a lot of money and asked Hazare to declare him his heir, a senior police official said.
The hand-written letter was sent around four days back to Hazare's office at his native Ralegan Siddhi village in Ahmednagar district, Additional Superintendent of Police Pankaj Deshmukh said.
"In the letter, the sender has threatened that January 26 will be the last day of Hazare," Deshmukh added.
The police officer said Hazare has previously also received similar anonymous threat letters.
Talking to PTI, Hazare's personal assistant Shyam Pathade, said, "This could be the tenth such letter received by our office and Anna has chosen not to comment on such letters as he does not fall prey to such threats."
ASP Deshmukh added that police are trying to ascertain whether it is an act of mischief. However, a case has been registered against unidentified person in this regard.
