The deep crack of the explosion interrupted the hum of Kabul's morning-rush-hour traffic. Seconds later a black tower of smoke rose into the sky over the center of the Afghan capital. It was 8:30 on July 7. Sirens began to scream toward the Indian embassy, which had been hit by a suicide bomber driving a white Toyota.

Two hours later a list of the dead and injured was pasted on the wall of Jamhuriat Hospital, which is on the same street as the embassy. People gathered around the piece of paper, squinting in the sunshine to see if any of their loved ones were among the victims.

A middle-aged woman named Nafisa Nawabi staggered away from the list and screamed. Tears poured down her cheeks.

"We lost so many people from our family," she cried out. She turned to a young woman. "Millad is dead. Is Marwa alive?"

"No," said the younger woman, whose name was Fereshta. "Marwa is also dead, and Shukriya is torn to pieces."

They held each other and sobbed.

Two young men, one in a long-sleeved black T-shirt and the other in a purple shirt, were crying and talking to the women. Omid Whaj, the man in the purple shirt, was the brother of three of the dead: 2-year-old twins Millad and Marwa and a 15-year-old girl named Spojmai. Their mother, Shukriya, who was Whaj's father's second wife, had also been killed. Shukriya's two surviving children-both little girls-were in the hospital.

Like most of the 58 people who died in what was the worst suicide bombing in Kabul to date, the mother and her five children had been standing in line outside the embassy waiting to apply for visas. They were planning a vacation to India.

Outside a Soviet-era apartment block in the Macroyan neighborhood of Kabul, a multicolored mourning tent was already set up. Ambulances brought three of the bodies in cheap wooden coffins. Family members opened them so that the mourners could take a final look at the lacerated faces of the dead children.

"They are not Muslims," Ahmed Shah, the father of the children, said of the people responsible. "They killed these innocent children. That's not what Islam says. They are not Muslims."

The following morning, a group of officers of the National Directorate of Security (NDS), Afghanistan's intelligence service, sat in a room in the service's detention center waiting for a prisoner.

The door opened and in walked a man the officers hoped might reveal some clues as to why suicide bombers are turning Afghanistan into a conflict zone to rival Iraq.

Rahmat Khan was skinny and nervous. He sat down on an office chair, touched the right side of his torso gingerly, and looked around the room, as if expecting someone there to hurt him.

He explained, through a translator, that he was from outside a village named Do Aw, in the mountainous region of Pakistan that stretches along the Afghan border. He had lived there with his sick, elderly mother. He had no siblings, his father was dead, and there were no other relatives in their single-room, mud-walled home. The house was a three-hour walk from the village. Khan did not have any friends.