A 15-year-old boy had his phone stolen after he was attacked by two men in Alfred Street, Kettering, on Saturday evening (February 28).
The victim was in Alfred Street with a friend when they were approached from behind by two men who assaulted him.
The incident happened sometime between 6 and 7pm.
Witnesses, or anyone with information, is asked to call Northamptonshire Police on 101.
Alternatively, phone Crimestoppers anonymously on 0800 555 111 or use the anonymous online form at www.crimestoppers-uk.org.