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The Murder Detectives, a three-part Channel 4 documentary following the real-life murder investigation of 19-year-old Nicholas Robinson, concluded on Wednesday. Director David Nath and Detective Superintendent Andy Bevan, who led the investigation, told the Today programme why they made the documentary.

"There's a willingness at the moment, especially among the police, to restore a degree of confidence amongst the public," Nath said.

There was "never a good time" to explain to the victim's family that the investigation would be filmed, but their success was "testament to... the family liaison officers who built that trust with them", Bevan said.