Night Shade by Lynne Ewing

Jimena was once the toughest chola in East L.A. No longer in a gang, she is still feared by many. Nothing scares Jimena. Nothing, that is, except the reappearance of Veto, who was once the love of her life. That terrifies her, because Veto was killed a year ago by a rival gang. Or was he? Jimena discovers that he has made a devil's bargain, which could cost both of them their lives.
Author Biography: Lynne Ewing is a screenplay writer who also counsels troubled teens. She is the author of the first two books in the Daughters of the Moon series: Goddess of the Night and Into the Cold Fire. Ms. Ewing lives in Los Angeles, California.