A man was struck from behind and had his phone stolen by a gang in a Northampton armed robbery.
The incident happened on Sunday, July 7, between 9pm and 9.15pm, when a man was walking in the underpass under the A43 leading to Lumbertubs Lane at the junction with Queenswood Avenue when he was attacked from behind by a group.
They struck him to the back of the head, causing injuries that required treatment, and stole his phone, Northamptonshire Police today said.
During the incident, one of the offenders produced a knife.
A spokeswoman for Northamptonshire Police said: "The first offender is described as a black man in his early 20s with short black hair, about 5ft 5in and wearing a grey Nike hoodie.
"The second offender is described as a white man in his early 20s, of slim build, with blonde/brown spiky hair, about 5ft 2in, and wearing a light green t-shirt and black shorts."
Anyone with information is asked to contact Northamptonshire Police on 101. Information can also be reported anonymously to Crimestoppers on 0800 555111.