A thief who used a plastic bag to threaten Post Office staff before escaping with some money dropped much of it as he fled the scene.
The man, who was white and in his late 40s or early 50s with short grey hair, went into Raunds Post Office in Brook Street just after 2pm on Tuesday, March 11.
He pointed a plastic bag at staff in the shop in an attempt to convince them he had a weapon, and demanded money.
After he took an amount of cash, he ran out of the shop, but dropped a lot of the stolen money in Brook Street.
He stopped to pick up some of the cash, but ran away in the direction of the Methodist Church before he could retrieve it all.
Witnesses to this incident or anyone with information about it can call the police on 101 or Crimestoppers anonymously on 0800 555111.