LONDON — Trading jokes and swapping leads, investigators from the FBI and Scotland Yard spent the conference call strategizing about how to bring down the hacking collective known as Anonymous, responsible for a string of embarrassing attacks across the Internet.

Unfortunately for the cyber sleuths, the hackers were in on the call too – and now so is the rest of the world.

Anonymous published the roughly 15-minute-long recording of the call on the Internet on Friday, gloating in a Twitter message that "the FBI might be curious how we're able to continuously read their internal comms for some time now."

The humiliating coup exposed a vulnerability that might have had more serious consequences had someone else been listening in on the line.

"A law enforcement agency using unencrypted, unsecure communications is a major fumble," said Marcus Carey, who spent years securing communications for the U.S. National Security Agency before joining security-risk assessment firm Rapid7.