Manu Oza, the arrested man, allegedly sent the email to the Delhi police immediately after the blast outside the Delhi high court on September 7. He had used the name of a most-wanted terrorist from the Federal Bureau of Investigation's list.
"Oza, 23, a resident of the Ghodasar area of the city, was arrested from Patan district on Sunday where he had been staying with friends for the last five months," Ahmedabad Police Commissioner S K Sinha told newsmen.
In the email, Oza had claimed the responsibility for the blast in Delhi, identifying himself as `Ali Saed El-Hoorie, a member of the Indian Mujahideen, Sinha said. The email was sent using a proxy server in Moscow.
Oza's was the third email to be received by the Delhi police regarding the blast, of the total four. He had said in the email, in coded language, that next target would be Ahmedabad, which led to massive security strengthening in the city.
Union Home Minister P Chidambaram had said then that the mail seemed to be sent by an amateur, as the numerical code used in it was very simple.
"The email was sent with the intention to strike terror and create an atmosphere of fear. Oza has been arrested under section 66 (F) of the Information Technology Act which carries maximum punishment of life imprisonment," Sinha said.
The police commissioner said that Ali Saed El-Hoorie, whose name Oza used, was on top of most-wanted list of the FBI. "Hoorie has a reward of USD 5 million on his head," he added.
According to the city crime branch, which investigated the email, Oza is a standard 11th dropout and he used to work in a call centre.
Five months ago, he had a fight with his father and left the home for Patan where he stayed with a friend, Rajkumar Yadav, and did some data entry job. After Oza saw the Delhi blast news on TV, he allegedly decided to send a prank email to terrorise the people.
The cyber crime cell of the crime branch traced the email's origin from the Internet protocol address and found that it had been sent from Yadav's laptop, using a USB mobile broadband connection.
Oza had sent the email without Yadav's knowledge, using the Internet connection registered in Yadav's name. When Oza -- who was brought before mediapersons -- was asked why he sent the email, he said, "For fun and to get famous quickly."
Sinha said, "Oza told us that after the Delhi blast he got scared for his family in Ahmedabad and to alert the police he sent the e-mail. There is no evidence of he having link with a terrorists organisation."
Oza also told reporters that after leaving the home, he had learnt to hack computers and servers.
He claimed that he had been duped by a placement agent, who had promised him a job in a call centre. "I was mentally disturbed because of my father," he added.
The city crime branch is also probing another email, similar to the one sent by Oza. Police believe that this email too is a prank, but they are not ruling out the possibility that it could have been sent by a genuine IM operative.