The FIR was registered against him on Friday, days after two cabin crew members, Mayank Sharma and KV Jaganatharao Rao, who were arrested earlier and released on bail, wrote to the police, seeking action against cops who put them behind bars in May this year by taking unwarranted action against them.
Sharma and Rao were arrested and jailed for 12 days after Karnik's complaint in May alleged that the two had posted "derogatory" remarks against the Prime Minister's Office, the national flag and the Supreme Court, while commenting on a strike by Air India pilots.
The duo were charged under Section 506(2) of the Indian Penal Code and Sections 66 A and 67 of the Information Technology (IT) Act, besides relevant sections of the Prevention of Insults to National Honour Act, 1971.
Later, the two were granted bail.
Rao has filed a complaint against Karnik on Friday at the Bandra-Kurla Complex cybercrime police station, accusing him of maligning his reputation and misleading the police on social networking sites Facebook and Twitter.