A man accused of murdering a teenager on New Year's Day broke down and admitted "I deserve exactly all I get", a court heard.

Yesterday, the jury was told Darren Carr turned up on the doorstep of his brother, Mark, at 9.30am on January 1 in a very distressed state.

At 5am that day, Bradley Whitfield, a 16-year-old student from Hallam Crescent East, Braunstone, Leicester, died from a stab wound to the neck following an altercation with a group.

Mark Carr told the court: "Darren told me he had been in a fight. He said it was bad and began to cry.

"He sat in my armchair with his head in his hands."

Darren Carr (35) and Nicola Faulds (32), of Caldecote Road, Braunstone, Leicester, along with a teenage boy and girl, who cannot be named for legal reasons, all deny murder.

Giving evidence yesterday, Mark Carr said: "All he said was he had been protecting his family. He said that, as they were walking down the street, they were shouted at by four lads.

"He said Nicola approached them and was hit by one of the lads. During the fight, the young girl was injured to her face.

"Darren said he had hit one of the lads. He was so distressed and worried.

"I'd never seen him like that. He said, 'I have got to go the police. I deserve exactly all I get'."

John Pugh, Darren Carr's stepfather, told the court he went with him to Hamilton police station at 1.30pm.

He said: "Darren told me he thought he had hurt someone real bad.

"He was in total bits and was crying constantly.

"He said, 'I might have killed him'.

"He said he had to go down to the police station to sort it out. When we got there, he said, 'I have come to give myself up'."

He was then arrested on suspicion of murder, the court heard.

The jury at Nottingham Crown Court also heard evidence from several forensic scientists.

Charles Stephenson, of the Forensic Science Service in Birmingham, said he found a perfect match for Bradley Whitfield's DNA on a sock taken from Darren Carr.

He said the chance of it not being from the victim's blood was a billion to one.

The court had previously heard how Bradley died after his head was kicked "like a football", but Carr's lawyer denied he ever kicked the victim.

Mr Stephenson said he also found evidence of Bradley's blood on a jumper, tracksuit trousers and trainer belonging to the unnamed teenage male defendant and on Faulds's jeans.

Roger Mann, also of the Forensic Science Service, told the court the stain on the teenage boy's shoe and Faulds's jeans were likely to be caused by "airborne", or flying, blood.

The court heard earlier this week how Bradley died from a 2.5 inch puncture wound to his neck outside Roxy's Chippy in Fosse Road South, Braunstone.

Yesterday, Mr Mann explained how a 27mm by 56mm shard of glass was removed from the victim.

He said it was later found to be embossed with a Smirnoff vodka motif and his team had painstakingly pieced it together "like a jigsaw" with the broken glass that was left strewn on the road.

The trial continues.