Putting the responsibility for the assassination of Benazir Bhutto on the country's "ruler", her husband Asif Ali Zardari on Friday rubbished the Pakistan government's claims that terror group Al Qaeda was behind the incident, saying it was trying to give a "new twist" to the whole episode.

He also demanded an investigation into the assassination by an international agency like the Scotland Yard.

"The ruler has to take responsibility for everything happening in the country," Zardari told CNN-IBN, without taking the name of Pakistan President Pervez Musharraf.

Zardari alleged the government was "not interested" in protecting the "most popular" leader of the country despite writing to the authorities that they were not satisfied with her security arrangements.

"We know we have lost our property. The Pakistan government is a bunch of people who are trying to give a new twist," he said.

He said the government was "playing a blame game and indulging in stupid debate. What we need is a serious debate", he said.

"The government is playing a game -- the ping pong," he alleged.

 When pointed out that the government was claiming that the family was against a post mortem on Bhutto, he said when he landed it was too late for any such action.

The  Pakistan government blamed Al Qaeda of being behind the assassination of Bhutto.