Officers are appealing for witnesses after a resident was threatened at knifepoint at a house in Richmond Road, Corby.
A man went into an address through the rear patio door, with a knife, and demanded money from the resident sometime between 4pm and 5pm on Tuesday, December 5.
The resident challenged him and he left, stealing a set of keys.
He made off on a white bicycle in the direction of Cottingham Road.
A police spokesman said: “The offender is described as a white, 5ft 9in chubby man with a stocky build and an Eastern European accent.
“His clothing was all dark and appeared padded, he wore a scarf up to his eyes and a beanie hat.”
Anyone with information can contact Northamptonshire Police on 101 or call Crimestoppers anonymously on 0800 555111.