A BBS set up by the Austin police department to act as a honeypot.

Infoworld (7 April 1986, p. 5) reported:
Underground Tunnel, which was set up to appear as a bulletin board run by a system operator called Pluto. But late last month - to the surprise of the board's more than 1,000 users - Pluto was revealed as Sgt. Robert Ansley, a seven-year veteran of the police department.
"Most of the users were people interested primarily in several on-line fantasy games or in electronic messaging," Ansley said. "To get to the levels where people posted information on how to crash corporate systems, the user had to ask for increased access. We were very careful not to solicit or entrap anyone into leaving illegal information."
The Austin police department disclosure caught most of the board's users by surprise. "I liked the board's electronic messaging capabilities," said user Michael Whalen, the managing editor of the Daily Texan, the student newspaper of the University of Texas here. "I was really surprised at how the officer was able to pull this off."
What the police found, according to Ansley, included access codes belonging to the world's largest credit reporting organization, TRW Information Services Systems Division of Orange, California. "Most offenders seem to be real big on TRW," said Ansley.

(Source: Infoworld, 7 April 1986; for some reason the report was reprinted in The Pirate World #1 without indicating that the bust had occured four years earlier).