Gilberto Reyes and John Sullivan are partners on the Narcotics unit for the Valley Enforcement Team. They are commonly known by other cops as Gilbert and Sullivan, although most younger cops probably don't know who that refers to. Ironically, Reyes looks very Caucasian while Sullivan looks Hispanic.
In April 2010 Harry Bosch contacted the two officers for information about Edward Roman . They could not provide the location of Roman, but they told Bosch where he could find Sonia Reyes, a prostitute that Roman had been living with.