Pakistani Christians said a Catholic businessman imprisoned for life for blasphemy was tortured and murdered and did not die of a heart attack as stated in a medical report.
The man was found dead in his prison cell.
"Qamar David might have fallen prey to an active hate campaign going on in the country on this issue by extremist groups," the Catholic bishops' national commission for justice and peace said in an update circulated by email March 15.
David, 55, died that day in "mysterious circumstances" in a Karachi jail.
At David's March 17 funeral, Father Andrew Nisari asked the congregation of more than 200 to be undeterred in their faith.
"Another historic chapter has been added in our struggle against the fatal logic," said the priest, referring to the blasphemy laws.