An Asian man who repeatedly stabbed a 17-year-old mother before pushing her into a canal to die saw white girls "simply as sexual targets", according to a judge.

At Sheffield crown court Ashtiaq Asghar, 18 of Rotherham, was found guilty of murdering Laura Wilson and sentenced to life imprisonment, with a minimum of 17-and-a-half years behind bars.

Wilson was stabbed a number of times in the head before being pushed into a Rotherham canal by Asghar in 2010.

The court heard how Asghar had probably used the knife to keep Wilson's head below the water.

Asghar and Wilson had been in a sexual relationship before she revealed all to his horrified Muslim family.

Before the murder, Asghar had been texting his friend and "mentor", Ishaq Hussein, 22, who was married and also had sexual relationship with Wilson, fathering her child.

"I'm gonna send that kuffar [non-Muslim] bitch straight to Hell," reads one of Asghar's messages.

Hussein was acquitted of murder in a separate trial.

"I take the view you came under the influence of Mr Hussein who is something of a mentor to you," said Lord Justice Davis.

"You no doubt had feelings for Laura, but treated her with contempt in the latter stages.

"Hussein seems to have regarded girls, white girls, simply as sexual targets. He does not treat them as human beings at all. You got into that mindset yourself."

He also described "elements of sadism" in Asghar's attack.

"One man has been convicted of Laura's murder and we're satisfied that all available evidence was put before a jury so that due process could take place," said South Yorkshire Police Detective Superintendent Mick Mason, the senior investigating officer in the case.

"This has been a traumatic time for Laura's family and friends, some of whom attended court. Her killer will face a lengthy prison sentence and we hope they can now move on with the rest of their lives."