Police are now linking the two attempted armed robberies in Market Harborough last week.
On both occasions, a man tried to rob the businesses armed with a knife.
Police praised staff for staying calm, which forced the robber to flee empty-handed in both incidents.
Officers now believe the attacks were carried out by the same person.
The two attempted robberies happened on consecutive days last week at GT News and Poundstretcher in the town.
The first attempted robbery was at the GT News / Post Office shop in St Mary’s Place, Market Harborough, last Thursday morning (February 9).
It happened between 8.50am and 9am, when the man, wearing a scarf across his face and a hood, so that only his eyes showed, walked into the shop and demanded money from staff at the GT News counter.
The staff stayed calm and did not hand over any money. The man panicked and ran off.
Witnesses say he turned left out of the shop, then looped back behind the shop to pick up his car - described as a small, silver hatchback type car. He then drove off down St Mary’s Road.
Sgt Kev Manship of Market Harborough police praised staff at GT News, saying: “Staff were very professional and kept their nerve.”
The second attempted robbery happened the next day - Friday, February 10 - at 5.30pm.
A man walked into Poundstretcher, which is on the Springfield Street side of St Mary’s Place, and threatened a member of staff with a knife.
Again staff remained calm, and the man ran off empty-handed, heading in the direction of the Waitrose store.
The man in both cases is described as white, in his early 30s, wearing a hooded top and a scarf over the lower part of his face.
Police are currently studying CCTV footage to see if there is a usable image of the robber.
If you have any information, you can call Leicestershire Police on 101.