A young British student was beaten with such severity that even his own father could barely recognize him.

Richard Danter, 31, was convicted this week in the murder of 20-year old Billy Mankelow. The two met on April 25 at Viaduct Show Bar in Leeds, where Danter worked.

Mankelow (above) left the bar with Danter willingly, but when they arrived at a nearby railway arch, Danter subjected his victim to an "unspeakable degree of violence." Mankelow died the next day.

Judge Peter Collier sentenced Danter to life in prison; he will serve at least 15 years before he is eligible for parole.

During the trial, it was reported Danter returned to Viaduct some 20 minutes after leaving with Mankelow. The panicky barback told staff he might have killed someone—but then departed again, saying he'd take care of the matter himself.

Danter (above) later returned to the Dark Arches, where witnesses saw him trying to drag his unconscious and half-naked victim by his legs. When he was spotted, Danter stopped and ran away and a passerby called for help.

Paramedics treating Mankelow said "his face was so badly swollen they could not examine his pupils or tell his ethnic origin," according to prosecutor Tahir Khan.

Mankelow was rushed to the hospital to operate on brain swelling, but he never regained consciousness. His father and grandmother, who traveled from Kent to identify the body, "barely recognised him because his injuries were so severe."

At court, it was revealed Danter had already served a lengthy prison sentence for robbing another student he met at the Viaduct. He also had a lengthy rap sheet, including indecent assaults and an attempted rape on an 18-year-old with a learning disability.

The defense attorney tried to paint Danter as having "a significant anger management issue, particularly when he has been drinking."

"An innocent, caring and popular young man died as a result of ...a totally unprovoked attack," said Detective Chief Inspector David Shipperlee of British Transport Police at sentencing. "His death is such a tragic waste of a young life; a life taken by a violent, evil and dangerous man, who has a history of previous convictions for violence and sexual offenses. [Richard Danter] is now where he belongs—behind bars."

Friends described Mankelow as "quiet" and nice, and, in a personal statement Ivan Mankelow called his son a "person of exceptional kindness and good nature."