An investigation into the assassination of a Christian Pakistani government minister who criticised the country's rigid Islamic blasphemy law is on "the right track," his brother said Thursday.

Shahbaz Bhatti, assassinated in March, was Pakistan's minister for minorities' affairs and campaigned for the rights of Christians before he was gunned down in Islamabad -- apparently by Islamist extremists.

"The investigations into the homicide of my brother are finally on the right track," Paul Bhatti, currently an adviser to Pakistan's government on religious minorities told the Catholic Fides news agency.

"It was committed by the Taliban and Islamist fanatics. Now, we are waiting for the capture of the perpetrators, who are in Dubai," he said.

He claimed investigators have determined that Al Qaeda's "Brigade 313", led by senior Pakistani Taliban Ilyas Kashmiri, asked a Taliban commander based in Punjab named Asmatullah Mawaia to kill his brother.

There were people who tried to suggest the official was killed by those close to him, but, "the truth has emerged," Paul Bhatti said.

"We were convinced that he had been killed for his work, for his defence of human rights and the rights of Christians. The investigation has proved us right," he added

Bhatti called for the investigation to be quickly concluded and for the culprits to be arrested, which, he said, "would be a good sign for the rule of law in Pakistan."

Bhatti was shot as he left his mother's home in a residential area of Islamabad. Police said the attackers fired at least 25 bullets at his vehicle.

A letter found at the scene, purportedly from supporters of Al-Qaeda and the Pakistani Taliban, claimed responsibility for the killing.

AFP