Pakistan's former President and head of the All Pakistan Muslim League (APML) political party Pervez Musharraf salutes at his residence in Islamabad in this April 15, 2013 file photograph.  [Photo/Agencies]

ISLAMABAD - Pakistani investigators have formally included former President Pervez Musharraf in the list of main accused in the 2007 assassination of former Prime Minister Benazir Bhutto, lawyers said Tuesday.

The Federal Investigative Agency (FIA) submitted a charge-sheet against him in the Anti-Terrorism Court (ATC) in Rawalpindi.

The FIA presented a four-point charge sheet against Musharraf in the ATC, accusing him for hatching a conspiracy, in connection with the assassination of former Prime Minister Benazir Bhutto.

Benazir was assassinated in a suicide attack and gun shots outside in Rawalpindi on December 27, 2007, after she addressed an election campaign rally.

The charge sheet submitted contained the statements of four witnesses, including an American journalist Marc Siegel, as well as Benazir's own statement.

FIA officials said that the charge-sheet has been prepared on the basis of Marc Siegel's statement, who had claimed that Musharraf called and threatened her when he was sitting with Benazir Bhutto.

Marc Siegel, who has served as lobbyist for Benazir Bhutto in the U.S., had also stated that Benazir had told him that Musharraf would be responsible for any harm to her.

He had earlier stated that he was with Benazir Bhutto in London when former President Pervez Musharraf had denied the allegations.

The charge-sheet stated that the statement of the American established Musharraf as the prime accused in Benazir's murder.

The charge sheet also leveled terrorism accusations against the former president. The document stated that Musharraf has failed to prove his innocence in the case.

The ATC last year summoned Mark Siegel to personally appear in the court and record his statement. However, he has not yet appeared before the court.

The ATC judge, Chaudhry Habib-ur-Rehman, ordered Musharraf must be produced in the court on July 2, when the court will resume hearing of the case. The court asked the police to ensure security for the former president.

Musharraf was not produced in the court on Tuesday over security concerns.

The former president was charge-sheeted in the Bhutto's murder case a day after Prime Minister Nawaz Sharif announced to initiate high treason case against him for abrogating the constitution.

Musharraf has been arrested in the murder case of a tribal elder, Nawab Akbar Bugti, who was killed in military operation in 2006.

He has been kept at his home in Islamabad over security concerns. His house has been declared as a sub-jail.