Photo: Jerry Lara /Staff Photographer Photo: Jerry Lara /Staff Photographer Photo: Billy Calzada /Staff Photographer Photo: /Courtesy Of The Castilleja Family. Photo: Billy Calzada, Staff / Staff Photographer Photo: Billy Calzada, Staff / Staff Photographer Photo: Courtesy Of The Castilleja Family.

Bexar County District Attorney Joe D. Gonzales said he moved Thursday to drop murder and assault charges against a 16-year-old Madison High School student who fatally stabbed an 18-year-old graduate of the school during a fight early March 1.

The girl’s lawyer said a witness bolstered her client’s version of events. She had been in custody since that night, held without bail in the killing of Kaitlin Castilleja, 18, a Texas State University student, and the wounding of Vivian Foster, 20, after the pair went to the juvenile’s home.

Police said Castilleja went there to confront her and the encounter took place in her driveway.

“Today, charges were dismissed against the 16-year-old respondent due to recently discovered evidence of self-defense,” Gonzalez said in an emailed statement. A spokeswoman for Gonzales said she was not authorized to provide any further details.

The girl has not been identified because she is a juvenile. Her lawyer, Libby Wiedermann, said prosecutors interviewed a 20-year-old late last week who was “working with” Castilleja and Foster and “set my client up to come outside.”

The 20-year-old, who Wiedermann did not name, “confirmed what we’d said all along, which is that my client did not know these girls were coming.” She said the 20-year-old, who knew both Foster and the juvenile, invited the teen to go somewhere that night “so that she would be outside so they could come and attack her.”

While she was outside, Castilleja and Foster approached her “with hoods covering their heads and part of their faces, and jumped her,” Wiedermann said. “Coincidentally, and luckily, she had that knife in her pocket and defended herself. … She was not trying to kill anybody.”

“I’m sure the families of both girls are very upset, and I understand,” Wiedermann said. “One of their family members was hurt and one was killed, which is terrible.”

Relatives said a long-running feud over an ex-boyfriend escalated to Castilleja and Foster going to the teen's home near Judson and Stahl roads to confront her.

Videos of the juvenile on her Twitter page contain taunting and confrontational tweets and a video shot by someone else of her fighting another girl at school. The social media profile of Castilleja also contained aggressive posts and boasts of physical violence.

Heather Doyon, Vivian Foster's mother, has said her son, Nick Foster, was anxious and had sent a text to Castilleja before the encounter, and described the message she saw on the phone as, “I don’t think you should go over there. I have a bad feeling about this.”

Madison senior Aaliyah Latiker, 18, has said she and Vivian Foster went with Castilleja because they didn't want for her to go by herself and that they “wanted to scare her. That was it.”

Vivian Foster has declined interview requests. Doyon said Thursday that Castilleja had texted Foster to say she was going whether or not Foster came with her. It was a “bad decision” for them to go to the girl’s house, but “they didn’t go over there with knives in their coats to stab” her, Doyon said.

“Everyone’s blaming Vivian for this,” she said. “I can’t say that my daughter could have done more.”

Wiedermann, however, said Foster was working with the 20-year-old witness to lure the 16-year-old out of the house. The 20-year-old “was on the phone and texting my client at the same time, while making calls and texting with Vivian Foster,” the lawyer said.

Wiedermann said her client “had no idea she was going to be attacked,” and had put a knife in her pocket because other things earlier that evening had put her on edge and made her fear for her safety.

Doyon said the 16-year-old could have called police if she felt threatened.

“She knew that the girls were outside of her house,” Doyon said. “If you feel threatened like that, as a 16-year-old, you don’t put a knife in your coat and walk outside.”

Social media posts from the 16-year-old before the fight alluded to her intention to harm Castilleja and “too many things don’t add up to just drop the charges and go on about your life,” Doyon said.

“It’s a terrible thing that happened,” Doyon said. “I do feel for (the girl’s) parents, I couldn’t imagine watching one of my kids go though this. I feel for Kaitlin’s parents, I couldn’t imagine losing one of my kids.”

Latiker has said she waited some distance away and could not see much of the fight. Foster was cut in the chest and arm, and then Castilleja came out of the darkness, holding on to her bleeding neck, she said.

On ExpressNews.com: Witness describes frantic scene after late-night fatal stabbing of Madison High School grad

Latiker said they put Castilleja in the car, and the wounded Foster frantically drove to Northeast Methodist Hospital while Latiker held a towel to Castilleja's neck. She later died at Brooke Army Medical Center.

The juvenile faced a charge of aggravated assault with a deadly weapon in addition to the murder charge. She was “in disbelief” and “very happy” when told the charges were being dropped, and was released from detention around 4:30 p.m., Wiedermann said.

“I wish the case had been investigated fully first before she was arrested, but I’m very thankful and very appreciative that the District Attorney’s Office did the right thing.”

On April 11, the DA's Office filed a motion to certify the juvenile to stand trial as an adult. Judge Lisa K. Jarrett later ordered the girl to undergo a psychological exam to provide evidence for that decision.

The girl is “welcome back” at Madison if she chooses to return, said Aubrey Chancellor, the North East Independent School District spokeswoman. “And we will work with her just like any other student.” She will also be given the opportunity to attend another campus in the district, she said.

Wiedermann said that her client and her family “were not even expecting to have her at dinner tonight,” so they haven’t made plans for whether or where she’ll return to school.

“It could be very difficult going back and getting that additional attention,” the lawyer said, including from people who knew Castilleja. “So it may not be the right thing for her. I’ll talk with her family about that.”

Elizabeth Zavala covers county and state courts in San Antonio. Read her on our free site, mySA.com, and on our subscriber site, ExpressNews.com. | ezavala@express-news.net | Twitter: @elizabeth2863