Dharamsala, July 24 - The family and friends of British charity worker Michael Blakey, who was murdered in this northern Indian hill station in November 2006, are not satisfied with pace at which the police investigation is going on in India.

They have shot off a letter to the Foreign Office asking them to put pressure on Indian authorities to help the British government in tracing the killer.

However, local police say they are hampered by the absence of a probable suspect, who has since emigrated to Scotland.

The body of Blakey, who worked with an Indian charity running community-based projects in the Kangra valley, was found beneath boulders in a shallow stream running through an old British cemetery here in November 2006. He had been bludgeoned to death.

Police suspected the involvement of Pawan Bhardwaj, the Indian husband of Blakey's colleague Rachel Owen. He was arrested by the police a few days after Blakey's murder and questioned for several days but was later released without charge. He later migrated to Scotland along with his wife.

'We are re-investigating the murder of Michael Blakey... so far more than 20 people have been interrogated,' Deputy Superintendent of Police Dinesh Sharma, who is the new investigation officer in the case, told IANS Friday.

'Our investigations are primarily on the basis of the report of a coroner's court in Britain. But there is no substantial evidence in the report,' he said.

The Lancashire coroner's court has sent an inquest report to the Indian police that includes statements of Blakey's colleagues and friends, including Owen and Bhardwaj, and Blakey's post-mortem report.