A man was robbed by a group of teenagers as he walked in Kettering on Friday night.
As the man, 19, was walking along Regent Street, he was approached by three teenage boys and a teenage girl.
They pushed him into the porch way of a house, where they demanded items from him.
The incident, which took place between 8.30pm and 8.40pm on April 5, was disturbed by a local and the four made off towards Bath Road.
A Northamptonshire Police spokeswoman said: "The first offender was white, around 14-years-old and 5ft 8ins.
"He was of slim build, had dirty blonde hair and was wearing a grey coloured zip up hoody.
"The three other offenders were also teenagers with the girl described as black, of large build, with braided hair and wore a black jacket."
Officers would like to speak to anyone who may have witnessed this incident or who may have any information regarding it.
Witnesses or anyone with information is asked to contact police on 101 or Crimestoppers anonymously on 0800 555 111.