A sadistic killer who stabbed to death a 14-year-old he met online was arrested over claims that he raped another teenager but was released almost three years before the murder.

Computer engineer Lewis Daynes, 19, has pleaded guilty to the murder of Breck Bednar, who was found with a fatal neck wound at a flat in Grays, Essex, on February 17 last year.

He is due to be sentenced at Chelmsford Crown Court later today.

Mrs Justice Cox lifted restrictions which prevented the reporting of five other counts that Daynes faced.

These included four counts of sexual offences relating to another victim and one of possessing indecent images. Daynes has denied these offences.

Prosecutor Richard Whittam QC said there was no longer a realistic prospect of a conviction, given he had admitted murder, and the charges will not be proceeded with.

It is understood the offences were reported to Essex Police in 2011 and were investigated but officers decided not to take any further action.

The crimes were then reinvestigated as part of the murder investigation and charges were brought.

The matter has since been referred to the Independent Police Complaints Commission (IPCC), which is investigating this along with other matters raised by the Bednar family.

The previous allegations were one count of rape, one of attempted rape and two of engaging a person in sexual activity without consent, the Crown Prosecution Service said.

Both Daynes and his alleged victim, who cannot be named for legal reasons, were 15 at the time of the incidents, which date back to between April 1 and July 10 2011.

The allegation of making an indecent image of a child dates back to August 30 2011.

Daynes, of Rosebery Road, Grays, previously denied murder but changed his plea on the day he was due to stand trial.

Mr Whittam told the court it was the prosecution's case that the murder "involved a sexual and sadistic motivation".

Family members said Breck, from Caterham in Surrey, left home after arranging to meet a friend online.

Outlining the prosecution case today, Mr Whittam said Daynes - who went by the online name EagleOneSix - befriended Breck over the internet and promised him "great wealth" through a fictional computer software business.

He said there was evidence of sexual activity between the two shortly before Breck, who was tied up by duct tape to his wrists and ankles, was killed.

Mr Whittam said: "Following the infliction of the fatal injury to Breck Bednar, Lewis Daynes disseminated images of his body to at least two people as well as making contact with a member of his online community to tell them that he was dead.

"He showered, then changed his clothes before calling the police."

The prosecutor painted a picture of Daynes as a controlling ringmaster of the gaming group.

"Daynes was the dominant party and exercised his power by barring would-be participants from his server when they displeased him," Mr Whittam said.

The day before the murder was the first time the pair had met in person.

"Only one person remains who knows what happened," Mr Whittam said.

"A pizza was ordered and delivered. The next contact with anyone outside the flat was the following morning."

A post-mortem examination found Daynes had slashed his victim's throat. The nature of Breck's injuries meant death would have been "very rapid", Mr Whittam said.

On the morning of February 17, Daynes made a 999 call and claimed Breck had tried to take his own life and, as he struggled to restrain him, he accidentally stabbed him.

During the call he spoke in a "cold" tone and gave an "entirely false account", the prosecutor added.

When police arrived, Daynes told them: "Look, I know he's dead, I stabbed the main artery in his neck."

Shortly before the killing, Daynes bought duct tape, condoms and syringes online.

Dressed in a grey suit, white shirt and tie, Daynes looked composed throughout the hearing, occasionally shaking his head at the prosecution case.

Simon Mayo QC, mitigating, said Daynes had Asperger's syndrome which "affects his ability to make sound judgments".

He added that Daynes did not accept that his behaviour had been sexual and sadistic.

Mr Mayo said: "There is insufficient evidence for the court to conclude that there was a significant degree of premeditation and planning for murder."