ALBUQUERQUE — Joan Marentes knew her career in the Albuquerque Police Department was over the moment a state worker said she was ineligible for public assistance. Assigned to the Crimes Against Children Unit, Marentes was a decorated detective, named Officer of the Year in 2009 for her work keeping kids out of harm’s way. Often those same kids ended up placed in the care of grandparents or other relatives. Now, in an ironic twist, she had taken emergency custody of her own granddaughter after learning the child was being abused by her parents. Like hundreds of other grandparents, Marentes trusted that the state would help her deal with the sudden financial stress of taking in a child.