Judge Castillo is a character from the 2000AD and Megazine epic - Judge Dredd - Wilderlands.
When Justice 4 crash lands on an uncharted planet, it's Judge Castillo that has to find the deserted outpost from which to contact Mega-City One and save the survivors (including Chief Judge McGruder and Judge Dredd).
On a later space mission (also with Dredd) to Lawcon (the first intergalactic law enforcement convention), the event is threatened by a sinister alien lifeform known as C-NIDARUS (capable of assuming the appearance and character of its victims).
Castillo is captured and killed while the aliens assume her appearance to disrupt the rest of the event. The plan fails and the aliens are killed, but this doesn't bring Castillo back...