New Delhi: Social activist Anna Hazare received an anonymous letter threatening him that he will be killed on this republic day. The police further revealed that the letter was received at Anna's office in his native village Ralegan Siddhi.

The sender claimed that anti-corruption leader has earned a lot of money and he asked Anna Hazare to declare him as his heir. Police said that the letter was received at Anna's office in his native village Ralegan Siddhi.

The letter was handwritten and was sent four days ago. Police said the leader had received similar letters earlier.

Pankaj Singh, additional Superintendent of the Police said that the adequate security has been given to Anna Hazare and the police was reviewing the situation on a daily basis.

Anna Hazare's personal assistant said that this could be 10^th such letter received by the office but Anna Hazare chose not to comment.

A case against the unidentified man was filed.

Anna Hazare who has been an anti-graft crusader became one of the key leaders in India following his movement against corruption in 2011. Arvind Kejriwal who was also part of the movement later joined politics and became the Chief Minister of Delhi. Anna decided not to join politics and remained a social activist.(Inputs from agencies)