HOUSTON (AP) — Police say an ex-boyfriend has been arrested and charged with murder in the killing of a 16-year-old Houston girl who was shot 22 times as she walked her dog.

Diamond Alvarez was killed Jan. 11 a couple of blocks from her home near a park. Houston police announced Tuesday that 17-year Frank Deleon was arrested Monday and charged with murder. Court records do not list an attorney who can speak on Deleon’s behalf.

Alvarez’s mother, Anna Machado, says Deleon was her daughter’s ex-boyfriend and that he had texted to ask her to meet him at the park shortly before she was killed. Machado says after she heard gunshots and couldn’t get a hold of her daughter, she rushed out of her home. After finding her daughter, Machado says she tried to perform CPR but could not save her.

Diamond’s family described her as an outgoing person. They said she was a hard worker and brought joy to everyone she met.