Islamabad: American journalist Mark Siegal has become the prosecution’s witness in the Benazir Bhutto assassination case, a media report said on Saturday.

Federal Investigation Agency prosecutor-general Chaudhry Zulfiqar said Siegal gave a statement saying then President Pervez Musharraf telephoned Benazir Bhutto in his presence and 'threatened' her when she returned to Pakistan before the 2008 elections, a news agency reported.

Bhutto replied that Musharraf would be responsible if anything happened to her.

Siegal further said in the statement that Bhutto appeared 'disturbed' after Musharraf's phone call.

Bhutto (1953-2007) was the first woman Prime Minister of Pakistan. She was twice the Prime Minister - 1988-90 and 1993-96 - but could not complete any term.

She was removed in 1996 as Prime Minister on charges of corruption, and went into self-imposed exile to Dubai in 1998.

Bhutto returned to Pakistan in October 2007 after an understanding with then president Musharraf. She was granted amnesty and all corruption charges were withdrawn.

She was assassinated in December 2007, after a Pakistan People’s Party rally in Rawalpindi, just two weeks before the scheduled election of 2008.

The prosecutor-general said a member of the investigation team recorded Siegal's statement in the US.

According to media report, Siegel was Bhutto's friend for almost 25 years. He also acted as her lobbyist and a key negotiator between her and the Musharraf Government.