Lau'Tan

Lucas Finch was a Gizou assassin posing as the Krillitane Brother Lassar. Using Lassar's human alias "Lucas Finch", he served as prosecutor when the Doctor was put on trial by the Shadow Proclamation. However, it was later revealed that "Finch" was a shapeshifting Gizou in disguise, and he was arrested by the Proclamation. The Gizou was working under orders from the Doctor's Advocate. (IDW: Fugitive)