Hugo Blake was, with his wife Kathy Blake, leader of the Blake gang. As with his fellow gangsters, he was influenced by Spandrin (who had possessed Jimmy Lynch) into seeking out and eliminating Trenix, eventually managing to track him down to Reynolds Hardware.
When Hugo went to kill Trenix with "Jimmy", Ray Lennon, Benny Malone and Frankie the Shiv, he witnessed Trenix transform into his Gesaurian self due to the Fourth Doctor's interference. This shock made him begin to break his conditioning, questioning why he was trying to kill Trenix and allowing him to see that his revolver was actually a Sinestran killrod. Spandrin then made Kathy kill Hugo, after which a Sinestran assassin possessed his cadaver. (AUDIO: The Sinestran Kill)