Indian police questioned a dozen people Thursday as a top foreign ministry official said New Delhi hopes Pakistan will help find and punish those responsible for the bombing of a train between the two countries that killed 68 people.

Police are searching for two men who jumped off the Samjhauta Express shortly before a pair of bombs detonated Sunday night, sparking a fire that engulfed two coaches and killed 68 people as the train headed through northern India for Pakistan. Sketches of the two men were released Tuesday.

Investigators were questioning a dozen people rounded up in New Delhi and in the states of Rajasthan, Punjab, and Uttar Pradesh, said Bharti Arora, a police official.

"Investigations are in a preliminary stage. There have been no arrests so far," Arora told The Associated Press.

Relatives have identified 33 of the 68 badly burned corpses — 27 Pakistanis and six Indians, said foreign ministry spokesman Navtej Sarna.

The bodies of 12 Pakistani nationals were taken home early Thursday, including the remains of six members of the same family whose funeral drew thousands of mourners.

Ambulances brought the remains of 43-year-old tailor Syed Iftikhar Ali, his wife and two of their children to Buffer Zone, a working-class neighborhood of Karachi dominated by Muslims who migrated from India to Pakistan during the bloody partition of the subcontinent at independence from Britain in 1947.

Dozens of relatives waited in the pre-dawn gloom — some in the street, others on rooftops — for the bodies to arrive. Men and women wailed and hugged each other as the coffins were unloaded and taken into the family's home. Throughout the area, shops remained closed and black flags were draped from electricity poles and lamp posts.

Ali's sister and brother-in-law also died in the attack, said Omar Ali, a 15-year-old son of the tailor. Their bodies were taken to a different district. The six had gone to India to attend a relative's wedding, he said.

"My father, mother, brother and sister are all gone. What will I do?" Omar told the AP in a voice choked with grief. He had stayed home with another brother to prepare for exams.

Thousands of male mourners later gathered in front of the wooden caskets outside the area's main mosque. Omar and his brother stood in the front row as a mullah led the funeral prayers.

Indian and Pakistani officials have said they believed Sunday's attack was an attempt to undermine their fitful peace process. They have vowed to cooperate in the investigation into the bombings and press ahead with efforts to end their nearly six-decade long conflict.

Their statements in the days following the blast were a break from the fingerpointing that often marked the aftermath of previous attacks.

But there have been reports in the Indian media — nearly all attributed to anonymous officials — that New Delhi believes Pakistan-based militant groups thought to be behind earlier attacks were responsible for the train bombing.

India's foreign ministry spokesman, Navtej Sarna, seemed to suggest as much Thursday, telling reporters: "We hope authorities in Pakistan will extend all cooperation in identifying and punishing the guilty."

He refused to elaborate.

Relations between Indian and Pakistan have been hostile since the bloody partition of the subcontinent into predominantly Hindu India and Muslim Pakistan after independence from Britain in 1947. A peace process that began in 2004 has helped ease tensions.

Indian officials have claimed there was Pakistani involvement in previous attacks in India, including the Mumbai bombings that killed 207 people in July. But most of the victims of Sunday's attack were Pakistani, helping assuage suspicions in India.

Results of an Indian investigation are to be shared with Pakistani authorities at the first meeting of a joint anti-terrorism initiative on March 6 in Islamabad, the Pakistan capital.