"We have received the letter from the newspaper and a probe is on," a senior police official said.
The letter, typed in English, says "Yesterday-Paris Charlie Hebdo, Tomorrow - Dinamalar." The words appear against the background of India's map.
The letter was sent by post by unidentified elements claiming to belong to an outfit called "The Base Moment," and said to be based at "3/10, Ukkadam, Kovai, Tamil Nadu, India."
Below the map is a picture of Osama Bin Laden and the words "By Al Qaeda," and some Arabic words appearing like a signature, the police official said.
Security personnel have been deployed at the office of the newspaper.
