One of Britain's most prolific paedophiles, who blackmailed a string of vulnerable victims including a girl who was ordered to eat dog food, has been jailed for 32 years.
Cambridge graduate Dr Matthew Falder has admitted 137 offences, including blackmail, voyeurism and encouraging the rape of a child, relating to 46 complainants after being caught by an international inquiry led by the National Crime Agency.
The 29-year-old was arrested in June last year after three traumatised victims, who were tricked into sending him humiliating images, attempted to end their own lives.
Sentencing "warped and sadistic" Falder (pictured) for "a tale of ever increasing depravity", Judge Philip Parker QC said: "As for your equally extraordinary sexual offending - no-one who knew you above ground had an inkling of what you were doing below the surface."
Branding him an "internet highwayman", he added: "You wanted to assume total control over your victims.
"Your behaviour was cunning, persistant, manipulative and cruel."
For the victims, he said: "The damage is on-going for these individuals it will never end, knowing the abuse caused by you still exists in other unknown persons' computers."
The judge, who also concluded Falder was a dangerous offender, added: "These sentencing remarks underplay your relentless, obsessive desire to continue committing offences."
A previous hearing was told Falder coerced male and female victims into producing "increasingly severe self-generated indecent images of themselves, the focus of these images being to humiliate and degrade".
Falder forced one victim to film herself licking toilet seats, a used tampon and eating dog food, and set up secret cameras in bathrooms to record women and girls naked.
Another was blackmailed into eating his faeces and drinking urine, while the 29-year-old also encouraged the rape of a boy, aged two, by his own father.
He also set up hidden cameras in publicly accessible toilets and at his parents' home, catching his unsuspecting victims on film, and using the footage to blackmail - and trade with others online.
Opening the facts of the case against Falder, prosecutor Ruona Iguyovwe previously told the court that many of the images were then distributed on so-called "hurtcore" websites on the dark web, showing material depicting sexual and physical abuse.
Falder, who treated victims both as sex objects and as objects of derision, posted on one forum "100 things we want to see at least once".
In remarks in that post, he suggested "a young girl being used as a dartboard", production of a video depicting a child's bones being "slowly and deliberately broken", and the abuse of "a paralysed child".
It also emerged during the earlier hearing that Falder initially duped victims into providing images by posing as a female artist who wanted to turn them into life drawings.
Prosecutors said Falder was also a member of several "virtual communities" of abusers, and in one such forum on the so-called dark web, he had a "membership rank level of 'Rapist'".
One of his victims, speaking anonymously after his sentencing, described how his abuse had led to the breakdown of "all relationships" in her life, and how she was now "scared to meet people".
The operation to catch Falder, who used specialist software to hide his online accounts, was aided by GCHQ, the United States Homeland Security Department and law enforcement bodies in Israel, Slovenia, Australia and New Zealand.
Falder, of Harborne Park Road, Birmingham, committed the offences over an eight-year period and never physically met any of his victims, but instead manipulated them from afar by duping them into providing nude images and personal details.
On his arrest, the former post-doctoral researcher in geophysics at the University of Birmingham told officers "what is it I've done", before correcting himself and adding "supposed to have done".
He then quipped that the list of suspected offences sounded "like the rap sheet from hell".
Copyright (c) Press Association Ltd. 2018, All Rights Reserved. Picture (c) National Crime Agency / PA Wire.