A teenager had his mobile phone stolen during an assault in Ilkeston in which he and his friend were punched and kicked.
The 17-year-olds were walking along Little Hallam Lane when they were followed by two others.
The attackers started making conversation with the teens, before punching them in the face and kicking them to the ground.
The incident happened on Thursday, August 21, at about 11.30pm but police have just released details.
A spokesman for Derbyshire Police said the first attacker was white, tall, and of medium build. He is believed to have been wearing a red sports jacket and had his eyebrow pierced.
The second youth was also white, of short, medium build and wearing a brown-coloured jacket. It is believed that they were both aged between 16 and 19 years old.
A leather jacket and a black Huawei mobile phone were also stolen
Anyone with information is asked to call DC Rob Nicholls on 101 or Crimestoppers, anonymously, on 0800 555 111.