The Cyber Cell of Chennai Police has registered a case after a rape threat was made on Twitter against the daughter of actor Vijay Sethupathi, who yesterday exited from "800" - a biopic on Lankan cricketer Muttiah Muralitharan - following opposition to his involvement in the project.

Without referring to Mr Sethupathi by name, or revealing details about the threat, Chennai Police Commissioner Mahesh Kumar Aggarwal tweeted: "There has been a lot of concern on social media regarding comments made against a celebrity. On receipt of a complaint to this effect a case has been registered."

The tweet, from a handle called @ItsRithikRajh, issued a graphic threat tagging Mr Sethupathi's own handle. Calling the actor a betrayer of Tamils, the tweet said: "Only this (sexual assault) would make him learn about the hardship faced by Lankan Tamils".

The Sri Lankan Tamils issue has always been an emotional one within the state.

There have been many allegations of torture, killing and sexual assault of Lankan Tamils by Lankan army personnel over the three-decade-long armed conflict between Tamils settled in the island nation and Lankan government forces.

The Tamils demanded equality and a separate homeland following reports of discrimination by the majority Sinhalese government. During the final phase of the war against the LTTE around one lakh Tamil civilians were reportedly killed.

Calling Mr Muralitharan a traitor and accusing him of supporting the killing of Lankan Tamils, veteran film director Bharathiraja, PMK chief Dr P Ramadoss and at least two ministers put pressure on Mr Sethupathi to leave the film.

Mr Muralitharan has denied the allegations and claimed that his statement on the end of the war was twisted. He later appealed to Mr Sethupathi to opt out of the project.

The cricketer explained: "I know the pain of war. I grew up in Sri Lanka amid war for over 30 years. My father was hacked when I was seven. Many times we were on the street."

Following Mr Muralitharan's appeal the actor yesterday said: "It's over."

Today's tweet triggered outrage, with DMK MP Kanimozhi calling it a cowardly act.

"The perverse intimidation of Vijay Sethupathi's daughter is not only barbaric but extremely dangerous to the very fabric of our society. Making women and children the soft targets is a cowardly act. The police should take stern action against the perpetrator," she tweeted. (NDTV)