“Goin jail. Think I killed sum1 (sic).”

A teenager has been jailed for a minimum of 19 years after stripping and beating a Chinese pensioner to death in Preston.

As reported by the Guardian, Nathan Richardson, 19, had taken a cocktail of drink and drugs at a New Year’s Eve house party. 67-year-old Wenqing Xu was out for a morning jog when he encountered the teenager.

Xu had been staying with his daughter, Diana, since last summer. The unprovoked attack left the pensioner from China with 28 areas of injuries to his head and neck and a laceration and bruising to his genital area.

Prosecutor Francis McEntee told Preston crown court that the motive remained a mystery.

Richardson was reportedly seen dragging the pensioner along the street but ran away after he was spotted by witnesses shortly before 8.30am. Xu weighed only 7st 12lb.

The Chinese father was found near Plungington community centre in Preston, badly beaten and wearing only a T-shirt that was pulled over his chest. He died in hospital the same morning.

Judge Mark Brown sentenced Richardson to life imprisonment, concluding that Xu had been in “the wrong place at the wrong time”.

He said, “The precise circumstances of the encounter are not clear but there is no doubt that you attacked him in a brutal, vicious and very cruel way.”

“He was subjected to a sustained and callous assault to his head and neck and I am satisfied he suffered additional degradation when you removed his lower clothing and dragged him along the street.”

“You were seen to be struggling with what was thought to be a roll of carpet, which you were pulling along the street. In fact it was Mr Xu.”

The judge said Richardson left his victim “dying in the gutter”.

After the attack, Richardson went to a house of a friend, Luke Jenkinson, on De Lacy Street. Richardson washed and changed his clothes.

Richardson then sent messages to his friends and family saying how he “kicked and stamped” on Xu’s head, describing how he pulled his trousers down and pulled him by his genitals.

Friends reportedly described him as laughing and “buzzing off it”.

The Sun reports that in a series of text messages to friends after the killing, Richardson said: “Goin jail. Think I killed sum1 (sic).”

“Fucked sum chink up. Bodied him. I think pure crime scene – his head’s gone,” he added.

Xu’s wife and daughter felt unable to complete a victim personal statement.

The judge said, “Such is the stress that this family have found it difficult to put into words the impact of his death upon them, but it is clear to me from Mrs Xu, as she is present in court and the distress written on her face, that the impact upon her and her daughter simply cannot be calculated.”

John Jones QC, representing Richardson, said he was “a young man with the most disadvantaged background and upbringing”. He added that Richardson was diagnosed with a personality disorder and learning difficulties.

Jones said, “He has pleaded guilty to the murder of an entirely innocent and respectable man. This has affected the defendant profoundly and he is sorry for what he has done.”

Jenkinson was also sentenced to two years and nine months in prison after admitting he assisted the offender.

DCI Gary Brooks, from Lancashire police, said: “In my 24 years with the police, I can honestly say I’ve never seen injuries as bad as those inflicted on Mr Xu.”

“When he left the house on the morning of 1 January he had no reason to believe he might not make it home.”

“His family, who have been left devastated by his death, had no reason to think it would be the last time they saw him alive.”