West Mercia Police helped to train an elite force in Bangladesh which has been accused of extra-judicial killings and human rights violations, according to the latest cables revealed by WikiLeaks.
Members of paramilitary group the Rapid Action Battalion (RAB) were trained by British authorities in "investigative interviewing techniques" and "rules of engagement", according to wires from US ambassador to Dhaka, James Moriarty.
Two officers from West Mercia Police organised two crime scene management courses for the Bangladesh Police and the RAB, while an associate tutor and officer from Humberside Police ran a two-week major investigation course for the RAB.
In a cable dating from May 2009 published by the Guardian, Mr Moriarty writes: "The US and UK representatives reviewed our ongoing training to make the RAB a more transparent, accountable and human-rights compliant paramilitary force.
"The British have been training RAB for 18 months in areas such as investigative interviewing techniques and rules of engagement. They said that the training had been widely disseminated within RAB and that they were undertaking an assessment of its effectiveness."
The latest revelations from the cache of US embassy cables also revealed British police provided training to members of the RAB to address the allegations of human rights abuses.
The National Policing Improvement Agency (NPIA) said it had provided courses to the RAB from serving police officers.
An NPIA spokesman told the Guardian: "The NPIA has given limited support to the Bangladeshi Police and the RAB in technical areas of policing such as forensic awareness, management of crime scenes and recovery of evidence.
"Throughout the training we have emphasised the importance of respecting the human rights of witnesses, suspects and victims."
He added the courses had been approved by the Government and the Association of Chief Police Officers (ACPO).
US authorities were legally restricted in the training they could provide because of the RAB's past record, which included "reports of abuses and a pattern of misrepresentation by the RAB regarding so-called 'encounter/crossfire killings"', the US cables said.
Despite its human rights record, the RAB, which was set up in 2004, had become Bangladesh's "most respected police unit", wrote Mr Moriarty.
The Foreign Office said: "We do not discuss the detail of operational counter-terrorism co-operation. Counter-terrorism assistance is fully in line with our laws and values."