WASHINGTON — Investigators from Scotland Yard have concluded that Benazir Bhutto, the Pakistani opposition leader, died after hitting her head as she was tossed by the force of a suicide blast, not from an assassin's bullet, officials who have been briefed on the inquiry said Thursday.

The findings support the Pakistani government's explanation of Bhutto's death in December, an account that had been greeted with disbelief by Bhutto's supporters, other Pakistanis and medical experts.

Also on Thursday, the Pakistani government announced the arrest of two more suspects in connection with the assassination plot but gave few other details.

It is unclear how the Scotland Yard investigators reached such conclusive findings absent autopsy results or other potentially important evidence that was washed away by cleanup crews in the immediate aftermath of the blast, which also killed more than 20 other people.

The British inquiry also determined that a lone gunman, whose image was captured in numerous photographs at the scene, also caused the explosion, said the officials, who spoke on condition of anonymity because the report has not been made public. Pakistani authorities originally said there were two assailants, based partly on photographs splashed across the front pages of the nation's leading newspapers.

Scotland Yard investigators verbally relayed their key findings to the government of President Pervez Musharraf on Thursday, as well as to Bhutto's relatives, according to the officials.

The findings are certain to be met with widespread skepticism, especially from her supporters, who blame the government for her death. In particular they blame Musharraf and the leading politician of the party that backs him, Pervez Elahi. Nor are the findings expected to calm the turmoil in the country at the end of the 40 days of mourning for Bhutto.

Even as the authorities in Islamabad prepared to receive the report, the government on Thursday announced that two suspects in Bhutto's death were arrested Thursday morning in Rawalpindi, a city about seven miles from the capital.

"All I can say is that two persons by the name of Husnain and Rafaqat were arrested today in the morning," said Javed Iqbal Cheema, a retired brigadier who is the spokesman for the Interior Ministry.

Last month, the authorities arrested a teenager from North-West Frontier Province in connection with the case and later made an additional arrest.