Johnathan Mosman - Child Porn Ring member pleads guilty

A Queensland police probe has led to the fifth member of an alleged child pornography ring pleading guilty in the US.

Johnathan Mosman, 47, of Connecticut, faces a minimum of 20 years and maximum of life in a US federal prison after admitting to four charges, including engaging in a child exploitation enterprise and conspiracy to advertise, transport, ship, receive and possess child pornography.

Mosman was one of 22 men in four countries, including two in Australia, arrested following an international operation that began on January 26, 2006, after a Queensland detective posing as a pedophile infiltrated the group via the internet.

The detective flew to the US and worked with the FBI's International Innocent Images Task Force. The FBI also sent agents to Australia.

The arrests dismantled what US authorities described as one of the largest and most sophisticated child exploitation rings, with more than 400,000 images and videos of child sexual abuse posted, traded, and trafficked.

The group used powerful encryption tools to keep the operation secret and a multi-layered system to vet new members, US authorities allege.

Mosman was the fifth of the 14 men arrested in the US to plead guilty to child pornography charges.

A trial for the remaining nine US defendants is scheduled to begin on January 5 in Pensacola, Florida.