A group of youths beat a 77-year-old man with one of his own crutches before stealing his mobility scooter, police said.
The pensioner was approached by three boys and a girl in Eastfield Park, Northampton, at around 6.30pm on Monday, who proceeded to attack him.
They kicked the vehicle and hit the victim with one of his walking crutches, before chasing his dog away.
They then stole the scooter, described as a red Invacare Leo, and made off in the direction of Finedon Road, Wellingborough.
The vehicle remains missing and Northamptonshire Police described the suspects as “three young black boys and a young black girl.”
Anyone with information is asked to call Northamptonshire Police on 101.