LONDON, Jan 16 (Reuters) - British police have travelled to Turkey as part of their investigation into the murder of Kenneth Bigley, a British engineer abducted and beheaded in Iraq in 2004, the Foreign Office said on Tuesday. "I can confirm that Metropolitan Police officers have travelled to Istanbul to carry out inquiries in connection with the death of Ken Bigley," said a Foreign Office spokeswoman. She declined to give further details about the police inquiry or who officers were seeing in Turkey. Bigley, 62, was kidnapped and later beheaded by a group led by Al Qaeda's then leader in Iraq, Abu Musab al-Zarqawi. Footage of the execution was shown on the Internet. U.S. officials said Zarqawi was killed in a U.S. air raid in June last year. The lawyers of a suspected al Qaeda militant on trial last year in Turkey said in April 2006 that their client had revealed Bigley's body had been buried near the Iraqi city of Falluja. The lawyers said the militant, Syrian-born Louai al Sakka, claimed to have taken part in the mock trial and sentencing of Bigley, but they did not say whether he was present at Bigley's beheading or had carried it out. Sakka was on trial charged with masterminding and securing money for bomb attacks on British and Jewish targets in Istanbul in 2003 which killed more than 60 people.