Four men arrested in connection with two armed raids on security vans in Nottingham have been released on bail.
Security staff were injured in the raids outside post offices on Trowell Road in Wollaton and Beech Avenue off Sherwood Rise on 21 and 27 October.
Police said two 19-year-old men, a 20-year-old and a 27-year-old were quizzed about the two robberies.
Nottinghamshire police said the investigation into the two attacks is continuing.
A security guard was threatened with a firearm and hit with the weapon before cash was stolen in the Wollaton robbery.
A female security guard who was delivering cash off Sherwood Rise was attacked and suffered a leg wound in the other incident.