Osama bin Laden's youngest son and close confidant is reportedly missing after the raid in Pakistan last week which killed his father.
Britain's Daily Telegraph says Pakistani officials believe Hamza, 20, may have escaped capture.
The newspaper reports three of bin Laden's widows, currently in custody in Pakistan, have told interrogators that one son hasn't been seen since the operation.
The White House initially claimed that Hamza, 20, had been killed at the house in Abbottabad, about 30 miles from Islamabad. Officials later said his 22-year-old brother Khalid had been killed instead.
On Tuesday night an intelligence source in Islamabad told the Daily Telegraph that shifting accounts of what had happened, coupled with the widows' testimony, left them unable to account for one person who they believe had been living at the house.
"We don't know if it was his son. Someone, one person may have been in the compound that we now cannot account for if - we believe what we are being told," he said.
Bin Laden, who was married five times, had as many as 24 children.
It's unclear exactly how many people were in the compound where bin Laden had lived for five years.
However, Hamza's mother is believed to be among the family members in Pakistani custody.
Hamza, thought to be the youngest of the Saudi-born warlord's sons, has been described as the "crown prince of terror". He featured on an extremist website to mark the third anniversary of the July 7 London bombings in which 52 people died.
Intelligence agencies believe he was being groomed as a possible future leader of al-Qaeda.
- NZ Herald staff