Ervin Robles

Ervin Robles is an Angel of Death-type serial killer who appeared in Children of the Dark along with his partner-in-crime Gary.

History
Ervin was placed in a foster home run by Mr and Mrs Manwaring, being separated from his biological sister Lucy as a result. While there, he was regularly abused and drowned. He formed an intense bond with Gary, who suffered even worse abuse. After moving out, Ervin became a criminal and served some time in jail, apparently for home invasion. After being released, Ervin took a job at the Denver City Pound. His official title was Animal Care Technician, but in practice, he was the primary euthanizer, developing an Angel of Death sense of mercy as a result. He still kept doing home invasions together with Gary. During a routine job at the Laybourne's house, they discovered that the parents had been abusing their daughter. As a result, Gary brutally killed them, and Ervin, as an act of mercy, killed the daughter by euthanizing her with pentobarbatol obtained from the Pound.

Gary and Ervin kept killing together that way two more times before the BAU was called in (Children of the Dark). When they killed the Ortiz family, Ervin felt that their daughter Carrie bore a striking resemblance to Lucy and accidentally injected the pentobarbatol into the soft tissue of her arm, missing the vein. She fled, was found wandering the streets and saved. Eventually, her descriptions led the the BAU to Ervin, who was arrested. Thanks to Carrie's presence at the interrogation, he was able to open up and give the authoritites more leads. He isn't seen again in the episode and has presumably been prosecuted.

Modus Operandi
Gary would gain the victims trust by bringing with him a cat euthanized by Ervin, claiming it to have been injured. Eventually, he let Ervin in, tied up and killed the parents. Afterwards, Ervin would take the children to a different room and euthanize them using pentobarbatol taken from the Pound.

Profile
Gary and Ervin together were profiled to be in their mid-to-late 20s, probably white, intelligent and organised. At least one of them has probably served time in for similar crimes. They probably use some kind of ruse to enter the houses. While Gary was profiled to be sadistic and remorseless, Ervin was profiled to be more withdrawn, sensitive and with a warped sense of mercy.

Known Victims

 * Presumably a number of victimless home invasions committed with Gary
 * The Lanbourne's unnamed daughter
 * The unnamed second family's children
 * Hayden Halbert and his unnamed brother
 * Carrie Ortiz (attempted) and her brother Danny

Appearance

 * Season Three
 * Children of the Dark