AHMADABAD, India - Police raided the home of an American living in Mumbai, India's financial capital, and seized a computer from which an e-mail claiming responsibility for bombings that killed 45 people in the city of Ahmadabad was believed to have been sent, officials said yesterday.

The 48-year-old American, identified in a New York Times report as Kenneth Haywood, general manager of an executive training firm called Campbell White, has not been detained, police said.

In Ahmadabad, antiterror police arrested an underworld figure with apparent ties to a banned Muslim group and were seeking to determine whether he had any connection to the weekend attacks in the city, deputy police chief Ashish Bhatia said.

Sixteen bombs tore through Ahmadabad around dusk Saturday, killing 45 people and wounding 161, state Health Minister Jaynarayan Vyas said. It was the second series of blasts in India in two days. Bombs killed two people a day earlier in Bangalore.

An obscure Islamic group took responsibility for the Ahmadabad attack.

"In the name of Allah the Indian Mujahideen strike again! Do whatever you can, within 5 minutes from now, feel the terror of Death!" said an e-mail from the group sent to several Indian television stations minutes before the blasts began.

The e-mail's subject line said, "Await 5 minutes for the revenge of Gujarat," an apparent reference to the 2002 riots in that western Indian state that left 1,000 people, mostly Muslims, dead. The historic Gujarat city of Ahmadabad was the scene of much of the 2002 violence.

India has been hit repeatedly by bombings in recent years. Nearly all have been blamed on Islamic extremists who allegedly want to provoke violence between India's Hindu majority and Muslim minority, although officials rarely offer hard evidence implicating a specific group.

Saturday's e-mail, sent from a Yahoo account and written in English, was made available to the AP by CNN-IBN, one of the TV stations that received the warning.

Police in Mumbai traced the e-mail back to the Internet protocol address of Haywood, who lives in Navi Mumbai, a satellite city across the water from India's commercial capital.

His firm's Web site said it offers "accent neutralization, cultural comprehension and verbal/non-verbal communication."

The Mumbai police said that he had been questioned but not arrested and that they were still investigating whether he could have been involved or whether his e-mail account was hacked.

"He is a suspect, yes," said a police officer involved in the investigation. "He may not be a suspect as well."

State Department spokesman Gonzalo Gallegos said Washington had no information on the detention. He offered condolences and called the attack a "heinous act."

In Ahmadabad, police arrested a man identified as Abdul Haleem who, Bhatia said, had ties to the banned Students' Islamic Movement of India and groups involved in the 2002 riots.

The group that claimed responsibility for the Ahmadabad attacks was unknown before May, when it said it was behind a series of bombings in Jaipur, also in western India, that killed 61 people.

In the e-mail, the group did not mention the Bangalore bombings, and it was not clear if the attacks were connected.