Former space scientist Nambi Narayanan Thursday filed a defamation case in a court here against former Gujarat director general of police R.B. Sreekumar for allegedly making "false statements".

Narayanan, a former scientist with the Indian Space Research Organisation (ISRO), alleged that Sreekumar tarnished his image by making false statements.

He said in his plea that Sreekumar made "vexatious statements" against him during a debate on a news channel in November last year.

The matter will be taken up by a court here Friday, court sources said.

The now retired scientist said the former police officer had also filed a "politically motivated" false criminal defamation complaint against him and others before a court here.

Sreekumar filed a defamation case in November 2013 against Narayanan, Bharatiya Janata Party's prime ministerial candidate Narendra Modi, party president Rajnath Singh and spokesperson Meenakshi Lekhi for hatching a conspiracy to defame him.

According to the petition, as part of the plan, Lekhi gave an interview to a TV channel where she alleged that Sreekumar played into the hands of America's Central Intelligence Agency (CIA), and falsely implicated Narayanan in an espionage case.

In 1994, Narayanan was implicated in an espionage case for allegedly leaking defence secrets to Maldivian intelligence officers.

Narayanan was then working as a scientist in the Vikram Sarabhai Space Centre, while Sreekumar was serving as deputy director of the Intelligence Bureau in Thiruvananthapuram (1992-1995).

However, a Central Bureau of Investigation probe found that Narayanan was innocent.