A witness saw three men trap an alleged murder victim in an alley before stabbing him, a court has heard.
Brothers Mustafa Aldobhani and Abdulgalil Aldobhani, along with friend Shafique Shaddad, deny murdering 18-year-old Fahad Nur in the early hours of June 2.
The prosecution say the defendants chased Mr Nur to a lane near Cardiff’s Cathays railway station where he was fatally stabbed 21 times.
The three men deny murder and are standing trial at Cardiff Crown Court.
A recorded police interview was played to the jury by prosecutor Michael Jones QC on Friday.
In the hour and 45-minute video, a witness of the alleged murder, Mohamaed Adam Mohammed, is interviewed by a South Wales Police detective via an Arabic interpreter.
Mr Mohammed said he was walking down a street while speaking with a friend on his mobile phone in the early hours of Sunday, June 2.
The interpreter said: “While he was walking there was a black man who was walking across the road in a straight line.
“He saw a man wearing a mask carrying a knife chasing after that black man.
“He was walking straight and the guy was coming from the other side of the street in the opposite direction.”
Mr Mohammed said there was a group of women behind him.
He said two men came from the other direction and he was “trapped in between them and then they hit him with the knife”.
Mr Mohammed said he told his friend on the phone what happened in front of him and his friend advised him not to get involved.
“He heard the five girls behind him say ‘ambulance, ambulance’,” the interpreter said.
“At the same time the three guys were running away from the area.”
He added: “One of the guys said something else and he couldn’t understand. He only heard the word ambulance from what he said.”
Mr Mohammed said the incident happened about three or four metres away from him.
The detective asked Mr Mohammed to describe the knife he saw the masked man holding.
“He says it was a small knife that we see around,” the interpreter said.
Asked to elaborate, the interpreter said: “It is impossible for him to remember the knife – the blade.
“He was walking and talking when this incident happened.”
Mustafa Aldobhani, 21, who does not have a fixed address; Abdulgalil Aldobhani, 22, from Cathays Terrace; and Shaddad, 25, from Louisa Place in Butetown, all deny murder.
Abdulgalil Aldobhani’s girlfriend Aseel Arar, 35, from Middle Park Road in Birmingham, denies assisting an offender.
The trial continues.