Police are trying to trace three girls who beat up a teenager and robbed her of her iPhone on a busy bus before bursting into fits of giggles.
The shocking footage was released by West Midlands Police after a 17-year-old girl was punched in the head as she sat on the number 22 bus on Broad Street, Birmingham.
It happened between 6pm and 6.15pm on January 2 as the bus was full of shoppers going home from the sales in the city.
As the victim tried to bravely fight back, another member of the gang snatched her iPhone out of her hand before being snapped giggling at each other.
The gang - who were all wearing leather jackets - then got off the bus at the next stop and fled in the direction of Sheepcote Street.
The terrified victim suffered bruising to her head and back following the robbery.
Detective Constable Alan Hands, from Birmingham West and Central CID, said: "This was a frightening attack for the victim as the three girls ganged up on her.
"She was fortunate to not be more seriously injured but she was left shaken up by what happened.
"We are appealing to anyone who recognises the girls in the images to come forward and contact us. If you have any information about those responsible, please call us as soon as possible."