Updated

A judge in Britain has sentenced a prolific pedophile to 38 years in prison in what is being described as a watershed moment for authorities coming to grips with technology's ability to spread depravity.

Geophysicist Matthew Falder admitted 137 offenses, including blackmail and encouraging the rape of a child.

Falder posed as a female artist to lure victims into sending him humiliating images, many of which were then distributed on the dark web. He approached 300 people worldwide.

Judge Philip Parker branded Falder an "internet highwayman," whose behavior was "cunning, persistent, manipulative and cruel."

Will Kerr of the National Crime Agency said Monday such crimes require "unprecedented" levels of resources to stop. The agency worked with U.S. Homeland Security, the Australian Federal Police and Europol to crack the case.