Social networking site Facebook says it has taken down two bogus profiles of Bilawal Bhutto, son of the murdered Pakistani politician Benazir Bhutto.
A number of news organisations were fooled, reporting details from the profiles before they were taken down.
Bilawal, 19, is an Oxford University student. He is now the joint leader of the Pakistan People's Party (PPP).
'Range of criteria'
It took a day or two for news of the hoax to emerge. By then several prominent news organisations in the UK and US had been taken in.
The hoax details followed messages of condolence sent after Benazir Bhutto was killed in a suicide gun and bomb attack in Pakistan a week ago.
One of the bogus profiles went under the name Bilawal Bhutto Zardari.
It carried a statement saying: "I am not a born leader. I am not a politician or a great thinker. I'm merely a student.
"I do the things that students do like make mistakes, eat junk food, watch Buffy [the Vampire Slayer] but most importantly of all... learn."
"Facebook examines a range of criteria to determine whether a profile is authentic, including reports from users, profile content, the e-mail associated with an account, length of time the account has been open and network affiliations," its statement said.
A spokeswoman for Facebook in London, Clare Gayner, did not say who she thought might have put up the bogus profiles.
She said controls were in place to stop people removed from Facebook from putting up new entries, but conceded there was nothing to stop them doing so under a different name.
She did not expect legal action against the hoaxers.
PPP officials made clear their party leader had nothing to do with the bogus profiles.
"It is not his posting, it is not by him, it is someone else who has done it," PPP spokeswoman Sherry Rehman told the AFP news agency. "It is a hoax."
An Oxford friend of the new PPP leader has been quoted as saying he does have a Facebook profile, under the name Bilawal Lawalib.
Since he became leader of his party, Bilawal has become the subject of numerous Facebook groups.
A picture of him in fancy dress as a devil has featured widely in the media. It was recently posted on Facebook, apparently by friends.