Benazir Bhutto's [Images] party on Friday rejected Scotland Yard's findings that the former Premier died due to the impact of a suicide bomb and not from a gunshot, insisting that a larger UN-led probe be carried out to expose perpetrators and financiers of the attack.

"It is difficult to agree with their (Scotland Yard) findings on the cause of the death," Pakistan People's Party (PPP) spokesperson Sherry Rehman, a close aide of Bhutto, said after the probe report by the British sleuths was released.

The Scotland Yard, in its report, backed the Pakistan government's conclusion that Bhutto died due to injuries suffered by her head hitting the escape hatch of her vehicle as a consequence of bomb blast and not because of bullet wounds on December 27 last year.

Rehman pointed out that forensic evidence at the scene of the attack at Liaquat Bagh in Rawalpindi was "hosed down" by the police within hours and the Scotland Yard team's "terms of reference were limited".

The British investigators "had to work under Pakistani police whose behaviour we had not agreed with," she said.

Rehman also said video footage clearly showed Bhutto had "recoiled from a bullet" shortly before the blast. "This gives us more cause to ask for a larger UN-led probe to expose the hands behind the person who pulled the trigger and the perpetrators and financiers of the attack," she said.

Additional Inspector General Abdul Majeed, who is heading the special police team probing Bhutto's killing, told a news conference in Rawalpindi,

"We are depending on Scotland Yard. They have given a categorical and definitive report and we are relying on it."

He said Pakistani authorities had so far arrested four persons -- Aitezaz Shah, Sher Zaman, Hasnain Gul and Rafaqat -- for alleged involvement in the assassination.

Majeed said Gul and Rafaqat, who were arrested in Rawalpindi on Thursday, were "apparently facilitators of the suicide bomber".

Majeed said the arrested persons had "given us useful information and we will shortly finalise a final report about them".