When on a freezing morning earlier this month, Andrei ended his shift as a night watchman at a small office in Chita, eastern Siberia, the car was waiting for him. "We're from the police," said one of the three men inside as they bundled him into the vehicle.

The men were from a local department responsible for investigating organised crime. For eight hours, police questioned him and tried to get him to sign a confession. If he did not, Andrei (not his real name) later told friends and colleagues, the men threatened to bring in for questioning his mother, who has a weak heart. Andrei signed - though he later went to prosecutors and wrote a statement that the confession had been obtained under pressure.