THE Police Office of Professional Responsibility (OPR) is investigating an allegation that two police ranks attached to the Kurupung Station have been involved in a corrupt transaction to release a dozen men who had been in custody following a shotgun find.A release said the 12 men had been arrested and detained at Kurupung Police Station on January 12, 2015 in relation to possession of an unlicensed shotgun and nine cartridges, and that the cops had been involved in a corrupt transaction with a view to having the men released from police custody.