A Brighton taxi driver picked up a man who is believed to have left another man bleeding seriously after a fight in the town centre.
Sussex Police said that detectives were now trying to trace the cabbie who is thought to have taken the suspect to Worthing.
The 22-year-old victim suffered a serious injury to his neck during a fight between a group of people in Castle Square, Brighton, in the early hours of Sunday (10 August) morning.
The violence involved people who had been involved in a number of arguments in the area on Sunday morning before the victim suffered his injury opposite a taxi rank.
He was taken to the Royal Sussex County Hospital in Brighton. His condition is currently stable.
The suspect was described as black and 22 to 26 years old. He was wearing a dark hooded top and jeans at the time.
He got into a Brighton and Hove green and white taxi after the attack.
Detective Sergeant Julie Greenwood said: “From our inquiries we believe the man travelled to Durrington or Lower Salvington in Worthing between 5am and 6am.
“We need to speak to the taxi driver who took him there. He may have vital information that could help us track the suspect down.
“If you were working in the early hours of Sunday and took a fare to Worthing, please contact us.”
Officers are also keen to speak to anyone who was in Castle Square when the attack happened and who saw the incident or what happened in the minutes before or after it.
Anyone with information is asked to phone Sussex Police on 101, email 101@sussex.pnn.police.uk or contact the independent charity Crimestoppers anonymously on 0800 555111.