A man has been convicted of murdering his on-off girlfriend hours after raping a stranger.

Marvin Samuels, 31, stabbed the mother of his young son 16 times and would have continued the frenzied attack if he had not hurt his hand, the Old Bailey heard.

Today, powerfully built Samuels, of Stonebridge, north west London, was unanimously convicted by a jury of murdering Sharlana Diedrick, 32, on September 29 last year.

Hours earlier he had launched a terrifying attack on a 42-year-old woman who was walking her pet chihuahua by Welsh Harp Reservoir in Neasden, north west London.

He battered the woman, who looked like his ex-girlfriend, after dragging her into the undergrowth.

He admitted rape and grievous bodily harm, but was charged with attempted murder, of which the jury cleared him.

He will be sentenced on Monday.

Samuels and the rape victim were complete strangers.

He attacked her with a bottle and a piece of wood.

Prosecutor Duncan Atkinson said ''she was in the wrong place at the wrong time but had a resemblance'' to Ms Diedrick.

He told the jury: ''Having raped he then beat her in particular using a piece of wood and caused her serious injury.

''Having left her for dead, two hours later the defendant then attacked Ms Diedrick as she sat in the seat of her car using a knife he had in advance.''

The attack on his former lover, with whom he had a "volatile" relationship, was carried out after he left the rape victim, who cannot be named, for dead.

Denying Ms Diedrick's murder, Samuels claimed he was not "mentally responsible" at the time.

The trial heard from a psychiatrist that while on remand Samuels had attacked inmates for looking at him.

The rape victim was unable to give information about what happened to her but forensic evidence was found linking Samuels to her.

Samuels told detectives that after pulling her in to the undergrowth he felt like he was ''lost in space'' and that he was ''feeling abnormal'' when he attacked her.

Mr Atkinson said: ''He then directed her to undress and started to choke her with her scarf and then struck her head first with a bottle and then a branch.''

Her ''naked and badly beaten body'' was later found when her worried husband and others carried out a search when she did not return home.

Ms Diedrick, with whom Samuels had a son, was found at 11.16pm that night with her body slumped halfway out of her Hyundai car which was parked near his home. Witnesses had heard her screaming.

Mr Atkinson said: ''She was covered in blood and a blood-stained knife was found near her. She had suffered 16 stab wounds to the chest and abdomen''.

Samuels said he argued with Ms Diedrick about child care for their son and he ''lost it completely''.

During police interview Samuels claimed he ''was not in his right mind that day'' and that Ms Diedrick had not been violent towards him, saying ''it was all me.''

Mr Atkinson also noted that Samuels said he would have hurt her more, had he not hurt his hand.

Saying he was pleased the jury rejected Samuels' claims of mental instability, investigating officer Detective Inspector Simon Pickford, from Scotland Yard's Homicide and Major Crime Command, said: "This has been a shocking case. Samuels has proven himself a violent predatory rapist and a murderer.

"He targeted a woman simply walking her dog, dragged her into woods, stripped her naked and then raped and savagely beat her.

"She will bear the mental scars of what happened for the rest of her life. She was so traumatised she has never been able to give us a full account of what happened."

He added: "He deserves to be behind bars for many years to come."

Online Editors