A paedophile carried on abusing children even as police gathered the evidence which would put him behind bars.
On Wednesday, 36-year-old David Wilson, from King's Lynn was jailed for 25 years for a string of horrendous child sex offences.
Roofer Wilson, of Kirstead, had earlier admitted 96 charges against 51 victims, including intentionally causing or inciting boys to engage in sexual activity, blackmail, intentionally causing children to look at sexual images and intentionally facilitating the sexual exploitation of children by sending on images of them.
Norfolk police first raided the modest semi he shared with his mother in 2015, after receiving information he was in possession of indecent images.
But Wilson was not at home when officers called because he was working away in Nottingham. And after he returned to Lynn to speak to them, he told them he had lost his phone on the train home.
A Norfolk police spokesman said: "David Wilson was arrested by Norfolk Constabulary on April 4, 2015 at an address in King's Lynn in relation to two counts of possession of indecent images between 4 March 2014 and 4 March 2015.
"Officers carried out a search of the property and investigated the matter, however found no evidence to link him to the crimes and consequently no action was taken.
"Due to ongoing concerns around safeguarding, he was subject to further measures through a multi-agency local authority designated officer meeting where a referral was made to the Disclosure and Barring Service.
Prolific paedophile from King's Lynn jailed for 25 years
"This meant employers would be informed of the concerns and the Football Association was also made aware as he had connections to children's football."
"In July 2017, the National Crime Agency became aware of a number of victims and identified David Wilson as the suspect shortly thereafter.
"Victims were located across the country, including Norfolk. Norfolk police supported the NCA investigation into Wilson."
The NCA had received information from Facebook about 20 accounts of boys ranging from 12 to 15 years old, who had sent indecent images of themselves to an account seemingly belonging to a 13-year-old girl.
The material was forwarded for investigation by NCMEC – the US National Center for Missing and Exploited Children – which receives industry referrals before forwarding them on to law enforcement agencies. What would become known as Operation Herculi got under way.
Tony Cook, the NCA's head of operations, said: "It was a really difficult, complex, lengthy operation which took us three years."
He added Wilson was probably one of the most prolific child sex offenders the agency had come across.
While he would eventually be charged with 96 offences against 51 boys aged from four to 14, officers believed Wilson may have had up to 500 victims, around one-10th of them in Norfolk and used social media to contact 5,000 children as far away as America and Australia.
"One of his victims was just four years of age," said Mr Cook. "He showed no compassion. Using unregistered phones, he pretended to be girls to get others to send sexual images.
"He built up trust then blackmailed them into sending more extreme images. Some said they wanted to end their own lives."
Detectives found the IP addresses used to commit the offences led to Wilson’s house and obtained CCTV footage of him buying a top-up voucher for a phone number linked to one of the fake Facebook accounts.
Wilson was arrested in August 2017. Officers found an unregistered pay-as-you-go mobile which had been used to access some of the girls' social media profiles. But it contained no messages or images.
"We were not in a position to charge him because we didn't have enough to prove the extent of his offending," said Mr Cook.
Messages exchanged on Facebook between Wilson and his victims were the missing parts of the puzzle.
So the NCA invoked MLAT - the mutual legal assistance treaty - to the US authorities, to request Facebook hand them over.
Wilson was arrested again in January 2018, because officers believed he was still offending. This time, they did not find a phone.
Records from Facebook were finally handed over in October, 2019. There were 250,000 messages, giving officers what Mr Cook said was "a significant challenge to process".
Gradually, they pieced together links between Wilson and five phones, seven fake female IDs and 14 social media accounts. The net was closing in.
"The phones were really crucial," said Mr Cook. "We had to prove David Wilson was the person behind the pseudonym."
Some details of the investigation have been withheld for operational reasons. But in April, 2020, the NCA learned Wilson had acquired another phone, and had been buying top-ups from a small shop in King's Lynn.
When they raided his house, he flushed it down the toilet. But technical experts were able to extract enough evidence to charge him with three offences and have him remanded.
By August, Wilson had been charged with 96 offences and his reign of terror was over.
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