The cyber cafe from which an email containing a threat to President A P J Abdul Kalam was sent has been located and four persons detained in this connection, a senior police official said in Indore on Friday.

"The email was sent to the President on July 19 at 4:51 pm and following a tip-off from Delhi, the cyber cafe was traced and four persons were detained by police," Superintendent of Police Anshuman Singh Yadav told reporters.

The cafe named "Cyber fun" is situated in Navlakha area and four computers were seized by police. The email was sent from the address dinesh-askn.yahoo.co.in and a person named Dinesh Sharma was among those detained.

However, it could not be said with certainty that he was the same Dinesh who had sent the email, Yadav said.

Two of the detained persons were identified as Wahab Baig, the owner of the cafe, and Vishal Malik. The identity of the fourth person was not disclosed.

"The investigation is still on and at present it is not possible to identify the main persons behind the incident," Yadav said.

He said the Special Cell of Delhi police has registered the case under Section 506 (punishment for criminal intimidation) of the Indian Penal Code and a police officer from Delhi is in Indore to help probe the matter.