A knife was used to threaten a man and a shop worker during two attempted robberies in Corby.
The first incident took place at about 8.30pm on Saturday, August 8, when a 57-year-old man was approached by a man while walking in Pytchley Court, Corby.
The offender walked up behind him and threatened him while holding a knife, demanding the victim hand over cash.
The victim walked away, at which point a member of the public shouted at the offender, causing him to run off towards Rowlett Road.
It is believed the same offender then went to the One Stop Shop in Studfall Avenue, at about 9pm, and threatened a member of staff with a knife, demanding cash.
The staff member pressed a panic button and the offender ran off.
The offender was a white man, 5ft 10in, and he wore blue jeans, white trainers and a dark jacket which was worn over a blue hooded top.
Police would like to speak to anyone who may have witnessed either incident or who may recognise the description of the offender.
Witnesses or anyone with information is asked to contact police on 101 or Crimestoppers anonymously on 0800 555111.