Ayub Khan of Vandoor and Abdul Basith of Pandikkad in Malappuram district were let off after detailed interrogation, the sources said.
The two students were suspected to have sent an e-mail on Monday to inshallah@sify.com similar to that of the December 16 message 'Long Live Osama Bin Laden' that emanated from a cyber cafe at Palayamkottai in Tamil Nadu's Tirunelveli district, they said.
During the interrogation, the students said they sent the message "only to play mischief" and had nothing to do with the December 16 incident, police said.
Tamil Nadu police, which was keeping vigil on the website, alerted their counterparts in Kerala Tuesday night after the students' e-mail, sent from an internet cafe at Pandikkad, was traced as part of their ongoing investigation, the sources said.
Perinthalmanna DYSP Rajmohan picked up the students from their residence at 10.30 pm Tuesday and they were grilled the whole of Wednesday to ascertain facts, police sources said, adding that they were finally convinced that the students had only done a mischief.
In the e-mail message, the students had reportedly picturised Parliament and Chennai airport besides repeating the words 'Long Live Osama Bin Laden,' police said.
