The child sex abuse crimes committed by HIV-positive Anthony Marsh's crimes were "especially deplorable," said Detective Inspector Delphine Waring of South Yorkshire Police.
"Knowing he had HIV, he chose to engage in sexual conduct with teenage boys and, in so doing, demonstrated a complete disregard for their wellbeing and future health," she said after Marsh and his accomplice were handed life sentences today.
"But, for Marsh and Davis's victims and their own families, today's sentencing will not be the end of the story," Ms Waring added. "The damage these two men have inflicted will last for many years to come."
The detective said it was possible more victims had not yet identified themselves and urged any people in that position to come forward for help.
Speaking after the sentencing of "predatory" paedophile Anthony Marsh and accomplice Lee Davis, South Yorkshire Police described the men's offences as "the most shocking series of sexual crimes committed against young boys" that the force has investigated.
The pair were said by police to have targeted boys across the country.
Marsh and Davis indulged their own depraved and criminal desires for many years against a number of young, impressionable and vulnerable young boys the length and breadth of the country.
The extent of their offending was matched only by the duplicity of their behaviour, which included their use of pseudonyms and multiple mobile phones to disguise their true identities and the deceit they exhibited day after day to their own families.
– Detective Inspector Delphine Waring of South Yorkshire Police
The men, from near Doncaster, South Yorkshire, used social networks such as Facebook and Bebo, as well as specialist gay websites, to groom teenagers as young as 13, before meeting their victims to sexually abuse them.
Police found a library of films hidden in the cellar of Davis's home showing him abusing the boys.
Officers also established that Marsh distributed some of the footage over the web.
A full investigation will begin today into the cause of a house fire that left a two-year-old girl dead, the South Yorkshire Fire Service said.
"A team of firefighters wearing breathing apparatus entered the property and located the fire in an upstairs bedroom, the fire service said in a statement. "A young child was rescued from the bedroom but sadly died."
South Yorkshire Fire and Rescue Service have confirmed that their crews have a large fire at a recycling plant in Sheffield under control. The service still has 10 crews at the scene and expects to be dampening down for the next few days.
The crews did an absolutely fantastic job. We were worried it would spread to Veolia, with potentially hazardous problems.
That would have been likely to have resulted in evacuations. But the crews put fire breaks in and contained the fire to the premises.
Although there was a lot of black smoke, the plume mostly blew over an industrial area and we're confident it wasn't hazardous.
– Incident Commander Rick Rolt, South Yorkshire Fire and Rescue Service
Around 50 firefighters are tackling a huge blaze at a plastic recycling plant in the Attercliffe area of Sheffield. It broke out at about 2.30pm at an industrial unit. A thick plume of black smoke can be seen as far away as Doncaster.