A gang of five broke into the courtyard of a block of flats before assaulting two people inside the building.
The youths, who police say may have been armed, broke into the courtyard of flats in Nelson Street, Kettering, sometime between 7.30pm and 7.45pm on Wednesday (August 5).
After breaking in, two people were assaulted inside the building and a mobile phone was stolen.
A Honda Civic car parked outside the building was also damaged at some point.
The police helicopter was called into action to help with the search for the gang, and an ambulance also went out to the incident.
A police spokesman said: “Investigations into the incident are still ongoing and officers would ask anyone who knows anything about it to call them on 101.”