Leandro appears to be African-American man in his 30's or early 40's of reggae/rusta subculture, therefore, he's probably of Jamaican nationality.
Noriega is first seen briefly in the episode "There's Something About Harry", on the mugshot (second from the left on the top) on the board labeled "Confirmed victims" in Agent Frank Lundy's temporary office in the Miami Metro. He's later seen, this time with a full name, along with some other victims such as Alan Matherson, while Debra Morgan searches for the pimp of Teegan Campbell in "Finding Freebo". It means that Noriega may, or may not also be a convicted pimp, despite it's possible that Debra was just saying to Dexter that she searches for suspect, while she was just procrastinating and thinking about her good times with Lundy during Bay Harbor Butcher Investigation. It is also should be noted, that in the same scene Alan Elson and Buck Forester were shown with different names, possible continuity error by series crew, but, taking into consideration that Alan Matherson is correctly named, there's a good chance that man is really Leandro Noriega.