Iustus Lomeli was a merchant of flexible scruples in the Shambles. When the Guards met him, he looked to be around 30 and was dressed decently well, for operating in the Shambles. He had wavy blond hair in a ponytail, and was quite short and slender.
He was involved in the theft of Noira Langevin's necklace. It was in his hands that it was found, after having gone from Maze to Vrain, and then through Rieg, who ultimately lead the Guards to Lomeli. The latter gave the necklace to the Guards with some weak protest, all things considered.