Police want to identify and speak to this person following a serious assault in Hammersmith which left one man with a stab wound and another needing 14 stitches to his face.
The incident happened in the early hours of April 12, in King Street, when a large number of people in Hammersmith Town Hall were forced to evacuate the building after a fire alarm went off.
At around 1.15am, while waiting outside for firefighters to deal with the alarm, a verbal argument broke out between the suspect and people from the event.
The suspect then left, only to return a short time later and push a woman. A 25-year-old man confronted the suspect and an altercation occurred, a police spokesman said. The victim suffered a cut to his face which required 14 stitches.
A 39-year-old man also intervened and was stabbed in his arm.
The suspect then ran from the scene through the town hall into Riverside Gardens and towards Hammersmith Broadway.
He is described as a black man, aged between 16 and 18, approximately 5ft 9ins tall, slim build with short black afro hair.
He was wearing a dark blue hooded top with what looks like a number '35' on the front in white, and dark bottoms.
Detective Constable Simon Feighan, from Hammersmith & Fulham CID, said: “This was a vicious and unprovoked attack on two people who were celebrating an event and came to assist their friend who looked like she was in trouble.
“I am aware the CCTV is not very clear but there were a large number of people outside the town hall and I hope someone may know who he is from the distinctive clothing he was wearing.”
Anyone with any information is urged to contact DC Feighan on 020 8246 2505 or Crimestoppers anonymously.
