A student was temporarily blinded when robbers threw a corrosive liquid in his face as they stole his phone.
It happened at 1.30 am on Clumber Street in Nottingham and police have now released CCTV pictures of men they are trying to trace as part of the investigation.
The victim has since made a full recovery after being treated in hospital.
Anyone who recognises the men in the images is asked to contact Notts police on 101, or Crimestoppers anonymously on 0800 555111.
