Christians are a tiny minority in Pakistan. They are barred from running for president.

Mr. Fanish was arrested on Saturday in the village of Jathikai and charged with blasphemy, a statute often used against minorities in Pakistan, human rights groups say. A Muslim family accused him of desecrating a Koran, but his local supporters said the family claimed that he had been admiring their daughter.

Whatever the case, he was taken to a jail in Sialkot, the district capital, and after two days of police questioning he was found dead in his cell, touching off Christian riots.

On Wednesday, the provincial government ordered an investigation into the death and are investigating whether to charge the jail staff with negligence.

The inspector general of prisons for Punjab Province, Kokab Nadeem Warriach, declined to say whether he believed that Mr. Fanish’s death was allowed or perpetrated by police guards. He said by telephone that three prison officials had been suspended, and that the investigation ordered by the provincial government would conclude this week.

The police said Mr. Fanish had hanged himself in his cell, using a strip of material ripped from his clothing. The Joint Action Committee for People’s Rights, an alliance of more than 30 human rights groups, said in a statement that it had talked to witnesses who saw marks of torture on his body.