Villus Thed was a member of a telepathic species and a possible criminal in the 24th century. He had the ability to read the thoughts of those that were in close proximity to him. In 2370, Odo learned from a subspace transmission that Thed was travelling to Deep Space 9, and told his deputies to alert him of his arrival, as well as to keep him under constant surveillance. He also alerted them to stay "at least" five meters away from Thed so he wouldn't be able to read their thoughts. (DS9 episode: "Second Sight")