Police have released photographs of a man they want to speak over an armed robbery and an attempted raid.
Detectives investigating both incidents believe 38-year-old Darren Brady could hold vital information.
They want to quiz him about an attempted robbery at Mastin Moor post office near Chesterfield on August 6 last year.
It is believed he may also be able to help them with inquiries into a robbery at Ug Stores in Forest Fields, Nottinghamshire, in November, in which staff were threatened with a knife before cash was stolen.
Brady has links to Sheffield, Chesterfield, Matlock and Manchester.
Call police on 101.