Sex offender who targeted young boys on websites is HIV positive

And police fear that Anthony Marsh, 53, and Lee Davis, 39, who have already admitted a string of sex offences, may have had more victims.

The pair used social networks such as Facebook and Bebo, as well as specialist gay websites, to befriend boys before committing what police describe as “vile, horrendous offences”.

After grooming the boys online, salesman Marsh, who has the virus that causes Aids, and unemployed Davis would meet their victims and sexually abuse them.

The pair admitted a string of sex offences at Sheffield Crown Court last month. It was announced yesterday that prosecutors will not proceed with a small number of additional allegations denied by the pair and Marsh and Davis will now be sentenced in December.

South Yorkshire Police said Davis filmed teenagers at his home or in his van. Officers believe some of the footage shot by Marsh was distributed by him over the web.

Detective Inspector Delphine Waring, who led the investigation into Marsh, of Menson Drive, Hatfield, near Doncaster, and Davis, of Rowena Road, Conisbrough, near Doncaster, said they were both family men whose wives were unaware of what they were doing.

She added: “Their crimes are absolutely despicable. They’ve preyed on vulnerable young boys who have every right, in this day and age, to be able to experiment and use the internet.”

The detective said there was no evidence Marsh and Davis knew each other before they met online.