A teenager has been arrested on suspicion of attempted murder after an alleged attack in Derby city centre.
The incident happened on Sunday, November 25, after a taxi driver was found critically injured at the Morledge.
Three men aged 23 and 24 were also arrested and released on police bail last week.
The man, who has been identified by family as Faisal Raja, remains in a critical condition, according to Derbyshire police.
Officers also want help to trace two other men connected to the alleged attack.
Detective Sergeant Gavin Owen said: “Today we have made a further arrest in relation to the incident, but are still appealing to the public to help us identify two other men.
“I’d urge anyone who recognises these men to get in touch with us as we believe they may be able to assist with our investigation.
“Equally if you have any other information about this incident, we’d be keen to hear from you.”
Anyone who may have any information is being asked to contact police on 101, quoting the reference number 18000569921 and the name of the officer in the case, Detective Sergeant Gavin Owen.
People can also call Crimestoppers, anonymously, on 0800 555 111.