The anonymous service contained more than 8.5 million images of child abuse.
A Dublin man has been sentenced to 27 years in prison in the US.
Eric Eoin Marques was described as the world's largest facilitator of child abuse imagery
He pleaded guilty to conspiring to advertise child abuse images on the dark web between 2008 and 2013.
The 36-year-old was extradited to the US by Irish authorities two years ago to face the criminal charges.
Prosecutors said his anonymous service contained more than 8.5 million images of child abuse.
Almost 2 million images involved victims not known to officers.
