— Police in India detained three men for questioning in Kashmir Thursday in connection with a bombing at a New Delhi court complex Wednesday that killed 11 people and injured at least 76, the Associated Press reported.

The blast, from a bomb hidden in a briefcase, occurred outside the reception area of the Delhi High Court complex during the morning rush hour, shortly after 10 a.m.

In an e-mail received by an Indian news television station, a Pakistan-based group called Harkat-ul-Jihad al-Islami asserted responsibility for the blast. The
e-mail said the al-Qaeda-inspired group, which also has cells in India and Bangladesh, would target several courts across India, including the Supreme Court, unless authorities immediately rescinded the death sentence of Afzal Guru, a Kashmiri convicted for his role in a 2001 attack on India’s Parliament.

A clemency petition from Afzal was recently rejected.

Security officials said they were examining the e-mail’s authenticity. “This could even be a smoke screen, maybe meant to distract us,” one intelligence official said. The official said the Harkat-ul-Jehadi cell in Kashmir has been weakened because of a series of arrests and surrenders.

Early Thursday, police in Kashmir said investigators had traced the e-mail to an Internet cafe in Kishtwar, in Kashmir, and they detained three residents of the town for questioning, including the owner of an Internet cafe.

A security official in Kashmir said the two-line e-mail was sent three hours after the bomb blast in New Delhi, by an 18-year-old man. An assistant at the cyber cafe told the official that the sender of the e-mail spoke a local dialect that indicated that he was from Kishtwar.

Authorities also were searching various locations in Kishtwar for clues, the Associated Press reported.

Also Thursday, the Indian news station Headlines Today received an e-mail from an indigenous militant group, called Indian Mujahadeen, which also claimed responsibility for the attack. Indian Mujahadeen is accused of carrying out a series of bombings in several cities since 2007. The news channel said it sent the e-mail to the Home Ministry for verification.

India’s top internal security official, U.K. Bansal, said preliminary investigation of the blast site turned up traces of nitrate-based explosives and pentaerythritol tetranitrate, known as PETN, which he called “the explosive of choice for terrorists.”

Unlike in some earlier attacks, Indian officials and police appeared reluctant to jump to conclusions or point a finger immediately at Muslim groups or neighboring Pakistan, with which New Delhi began a fragile peace process this year. In 2007, India was quick to blame Pakistan for a train bombing, but a subsequent investigation pointed to the involvement of radical Hindu groups based in India.

“There is a directive that has gone out that we will not name anyone in a hurry. It is because of the earlier mess-ups,” said the intelligence official, who spoke on the condition of anonymity because he was not authorized to talk to the media. He also said that there have been no substantial leads in any of the seven attacks across India since last summer. 

On Wednesday, however, New Delhi police released sketches of two people who they said might have brought the briefcase bomb to the court. Later, police in Uttar Pradesh state detained a 28-year-old laborer from a bus station because his face resembled the sketch of suspects.

Home Minister P. Chidambaram said in Parliament that the Indian capital is a target for terrorist groups and described the blast as “high intensity.” He appealed to citizens to remain “resolute and united.”

The court premises were evacuated immediately after the blast, and crowds of lawyers and litigants stood outside, watching bomb-sniffing dogs go in. A list of the injured was pasted on a wall of the court.

“It was a very powerful sound. I was on my way to the court to apply for bail for a relative,” said Amina Bi, an elderly witness. “When I reached it, I heard people crying and lying on the ground.”

The blast was the second in the vicinity of the court in four months. The first, at a parking lot in May, caused only minor damage. At the time, police theorized that it was a dry run for a future attack or a failed car bombing attempt.

Police promised then to install surveillance cameras outside the court entrance but have not yet done so. Lawyers at the court said metal scanners at the gate were not functioning Wednesday, either.

In Parliament, opposition lawmaker Arun Jaitley expressed outrage that the attack could occur in a supposedly high-security area of the capital. “I stand here with a sense of anger at the kind of a helpless situation we have been pushed into,” he said. “Have we become so vulnerable that terrorist groups can strike at will?”

The blast site is usually a scene of long lines of people waiting to get security passes. Dharmendra Kumar, special commissioner in the city police department, said the attacker could have kept the briefcase with the bomb near the line for maximum impact.

Angry relatives of the injured booed and shouted slogans at Rahul Gandhi, a leading figure in the ruling Congress party, who visited the hospital where many of the injured were taken to offer condolences. Outside the hospital, many relatives sobbed and pleaded with officials to let them in.

In July, three blasts ripped through crowded areas of Mumbai, killing more than a dozen people. But a police investigation of those explosions culled only a few weak leads and has proved inconclusive.