A magistrates court in the city on Monday signed an order issuing a letter rogatory (LR) to a Chicago court to allow the Mumbai Police Crime Branch to interrogate David Coleman Headley and Tahawwur Rana for their alleged role in the 26/11 Mumbai terror attack. If the Chicago court that tried Headley and Rana agrees to the LR,a team from the Crime Branch including Senior Police Inspector Ramesh Mahale the investigating officer in the case will travel to the US to gather evidence. Around two months ago,we had issued a request to the 37th Metropolitan Magistrates Court for an LR to interrogate Headley and Rana for their role in the 26/11 attack. The order has just been signed by the magistrate, said Joint Commissioner of Police (Crime) Himanshu Roy.