A lodger who stabbed a 13-year-old British girl to death after she claimed he had got her pregnant has been found guilty of her murder. The case has highlighted the difficulty UK police sometimes have in accessing evidence held by Facebook.

Stephen Nicholson, 25, has been convicted of murdering Lucy McHugh, who was stabbed and dumped at an outdoor sports centre in Southampton on 26 July last year.

Nicholson - who was jailed for life with a minimum tariff of 33 years on Friday - came to the police’s attention because rumours had been circulating at Lucy’s school about her having a sexual relationship with him but social services dismissed the allegation.

— PA Media (@PA) 18 July 2019

​But after she was found murdered, detectives immediately identified Nicholson as the prime suspect and sought to gain access to his Facebook page because they believed he might have messaged Lucy in the hours before she was killed.

© Photo : Family handout Lucy McHugh

Nicholson refused to give Hampshire Police his Facebook password and he was charged after he refused an order granted under the UK’s Regulation of Investigatory Powers Act (Ripa).

Jailing him for 14 months in August 2018, Judge Christopher Parker said he did not accept Nicholson's "wholly inadequate" excuse that if he gave the police his password it would reveal his dealing in cannabis.

— Daymo (@mcdaymo) 18 July 2019

​Judge Parker told him: "What you have done is obstructed the investigation, and a very serious investigation indeed. It has caused a very significant delay. It means that the task of police investigating the murder of Lucy McHugh is that much more difficult."

The prosecutor, Matthew Lawson, said police had been forced to follow a "lengthy procedure" to get the information from Facebook, who are based in California.

It was not the first time UK law enforcement has struggled to get help from social media companies in the US.

The Commissioner of the Metropolitan Police, Cressida Dick, is on record as saying is a "very protracted procedure" to access data from US social media companies.

Police in the United States also have to go through a fairly protracted procedure to gain access to Facebook data.

— Hampshire Police (@HantsPolice) 18 July 2019

​In 2013 Kyle Dube, 21, posed as a teenager boy on Facebook to lure 15-year-old Nichole Cable from her home in Maine. He staged her kidnapping so he could later rescue her and be hailed as a hero. Dube was jailed for 60 years in 2015.

The jury at Nicholson’s trial heard Lucy McHugh was told to “get out of her fantasy land” after she told her mother, Stacey White, she was being abused by the family’s lodger.

Her mother told her to “shut up before she ruined someone’s life”, the jury heard.

© Photo : Hampshire Police Stephen Nicholson

The trial was told Nicholson - who was a friend of Stacey White’s partner and had just come out of prison - deleted a series of Facebook messages between himself and Lucy in the hours before she was killed.

He told police Lucy had told him she was pregnant - which she was not-and demanded a meeting with him.

Nicholson stabbed her 11 times after immobilising her.

Her body was found in woodland at Southampton Outdoor Sports Centre in July 2018.

Nicholson was also convicted of three charges of raping Lucy when she was 12 and two counts of sexual activity with a child once she had turned 13.

On Friday the judge, Mrs Justice May, told Nicholson: "This was a pitiless attack on a child following months of sexual exploitation. The prosecution has described it as an execution and I am satisfied this is correct."

She said: "The combination of [his] cold narcissism and hot anger dictated that she had to be put out of the way and he saw to it that this was done."