The cyber cafe from where an e-mail containing a threat to President APJ Abdul Kalam was sent was located at a locality in Indore and one person arrested in this connection.
Police also picked up four to five people in connection with the e-mail threat and were interrogating them, a police official said.
The cyber cafe, known as "Cyber Fun", is situated in Navlakha area in the city, he said.
Delhi Police sources identified the arrested person as Manoj Joshi whose antecedents were not known immediately.
His interrogation was on to ascertain the motive behind sending the e-mail to the first citizen.
The e-mail was sent to the President's official website on July 17.
Police teams had fanned out across the city and a close watch was being maintained on cyber cafes, the official said.