[UPDATE BELOW]

An 18-year-old man has been arrested for a gang-related rooftop shooting on Friday that killed Zuranna Horton, a 33-year-old mother of 13, and wounded two others, including an 11-year-old girl. Police Commissioner Ray Kelly told reporters today that Andrew Lopez, 18, has made a full confession. Lopez was reportedly tracked down because someone sent a tip to the NYPD, which is exactly what outraged community members were hoping for.

“We’re certainly pleased with the fact that the investigation has identified Mr. Lopez and he’s made statements and apparently made a full confession,” Kelly told reporters today. Investigators believe Lopez opened fire from a rooftop onto a crowd of parents and students in a “retaliation” shooting, possibly related to a gang-related dispute involving his brother. Horton died instantly from gunshot wounds to her face and chest after she threw herself in front of schoolchildren to protect them. Police say she was not the intended target of the shooting.

Yesterday Natasha Capers, vice president of the PTA at P.S. 298 and also the mother of two students there, told the Daily News, "It's sad and it's tragic that a woman was killed doing the right thing. A woman sacrificed her life. What are the parents of \[P.S.\] 298 willing to sacrifice? We have to all come together for our children."

UPDATE: A police source tells the Daily News that Lopez's target was the 11-year-old girl Cheanne McKnight, who was grazed by a bullet. And the source says the shooting was sparked by an argument over a cell phone. McKnight and an unidentified 15-year-old girl were in a dispute over the phone, and the older girl complained to a friend named "Butter," according to the News. Butter, in turn, allegedly contacted Jonathan Castillo and his half-brother, Christian Lopez, got his half-brother, Andrew, to do the shooting.