The charges against a Madison High School student accused of stabbing two other teens, killing one, have been dropped, the Bexar County District Attorney's Office announced Thursday afternoon. "Today, charges were dismissed against the 16-year-old girl respondent due to recently discovered evidence of self-defense," said District Attorney Joe Gonzales. The teenager was facing serious charges, including murder. RELATED: Social media beef led to deadly stabbing on NE Side, police say The announcement comes less than three months after the district attorney's office wanted to try the teen girl as an adult for the slaying of Kaitlyn Castilleja, 18, and the stabbing of another 18-year-old.  On March 1, police said Castilleja and the other 18-year-old went to the girl's home as she returned from work and fought her in the driveway. The 16-year-old pulled out an undisclosed weapon and stabbed the pair, police said. Castilleja was taken to the San Antonio Military Medical Center, where she later died. Police said the incident stemmed from a series of ongoing social media exchanges that included threats. It isn't immediately clear what new evidence or developments the district attorney received that convinced him to dismiss the charges. RELATED STORIES: Teen accused of murder to remain in juvenile custody Medical examiner identifies 18-year-old fatally stabbed by teen in driveway Certification hearing set for Madison student accused in fatal stabbing