Connor Brown murder trial: Knife used to stab teenager to death had the words 'Joker - why so serious' printed on its blade

Connor Brown, 18, suffered five stab wounds to his chest and back and one cut to his arm during a fatal attack in Sunderland in the early hours of February 24.

A jury at Newcastle Crown Court has heard one of the wounds punctured his heart.

Prosecutors claim the teen, who had been on a night out with friends, had bravely stepped in when knifeman Leighton Barrass threatened to stab members of the public in a revenge attack after he had been punched on the nose by another man.

It is claimed Barrass's pal Ally Gordon joined in the fatal attack by "encouraging and assisting" Barrass by "kicking and stamping" on Connor.

Barrass, 20, of Hartside Square and Gordon, 20, of Polmuir Road, both Sunderland, deny murder and are being tried by a jury.

Forensic scientist John Newell has told jurors he examined items that had been collected by detectives during the course of the investigation.

Mr Newell told the court he examined a silver lock knife which had been found in the alleyway after the killing and has been shown to the jury.

He added: "On the blade there was printing, it said 'Joker - why so serious'."

Mr Newell said the knife was extensively blood stained and added: "In my opinion, in keeping with the knife being used to injure someone in a stabbing action".

The court heard a DNA sample taken from the blood on knife matched the profile of Connor and added: "The findings would be in keeping with the knife being used to injure Connor Brown in a stabbing action".

Mr Newell said profiles from three other people were found on the non-bloodstained parts of the knife but the findings suggested Connor and Leighton Barrass were the "main contributors" to the material that was detected.

He added: "It would be in keeping with Leighton Barrass handling the knife at some time."

Mr Newell said Gordon's DNA was not found on the weapon.

The trial continues.