A 71-year-old man was knocked to the ground and robbed in Corby as he walked home.
The attack happened in Orkney Way on Saturday (October 6) when the victim’s keys and cash were stolen.
A police spokesman said: “The man doesn’t remember much about what happened. He suffered a knock on the head but fortunately he wasn’t seriously injured.
“The attacker came from behind the man and we don’t have a description.”
Police are asking anyone with information on the robbery, which happened between 10pm and 10.30pm, to contact them by calling 101.