Three men have been arrested in connection with two armed incidents involving security vans in Nottingham.
Security staff were injured in the raids outside post offices on Trowell Road, Wollaton, and Beech Avenue, Sherwood Rise, on 21 and 27 October.
Police said two men aged 19, and a 27-year-old man were being questioned.
Officers have renewed appeals for information about a green Volkswagen Passat, registration R954 0NL, believed to have been used in both offences.
A security guard at the first robbery was hit with the butt of a firearm, while a guard at the second incident suffered a wound to the leg after a firearm was discharged.
Both required hospital treatment but the injuries were not life-threatening.