Police are appealing for any unknown victims of a paedophile who raped a baby to come forward.
John Maber was jailed for life on Wednesday for a catalogue of child sex offences, carried out at addresses in Bushey and Harrow.
However police are still investigating his case.
The 47-year-old prison officer’s vile double life was exposed when he offered to abuse a child over a webcam during an online conversation with police in New Zealand, who alerted the UK authorities.
Their intelligence was passed to the Child Exploitation Online Protection Centre, where Maber’s location was deciphered.
Within hours, Hertfordshire Constabulary officers were at Maber’s door in Oundle Avenue, Bushey, and seized his computer equipment, which detailed his own horrific child abuse, as well as hundreds of online conversations with other paedophiles.
As officers from the county’s Paedophile Investigation Unit discovered the volume of sickening material on Maber’s laptop, hard drive and iPhone, and the extent of his conversations with other suspected paedophiles, they decided to follow the leads themselves.
Detective Inspector Damien Kennedy, who led the investigation, said: “It was a policy decision I made not to just disseminate the information about the people Maber had contacted, but to travel nationwide to investigate.”
The officers travelled to Wales, Greater Manchester, Northumberland, Suffolk and Scotland, working with forces in those areas to find those they suspected had been in contact with Maber.
The investigations have to date led to 15 arrests and 30 children being protected.
Examination of Maber’s chat logs showed he spent hours scouring the internet for other paedophiles.
DI Kennedy said towards the end, before he was ensnared by New Zealand police, Maber was not cautious about who he approached online.
He said: “He was becoming frenzied.
"It was clear from the volume of chats logs he would chat continually, morning, noon and night.
"When these people ended the chat he would continue to attempt to carry on.”
Maber’s sentencing to life in prison on Wednesday is not the end of the case and officers are still pursing leads from his computer.
Hertfordshire Constabulary is appealing for anyone else who may have been a victim of Maber to come forward and contact the force on 101.