The girl shot and killed over the weekend in far southeast Dallas County was a 15-year-old Seagoville High School freshman.
The sheriff's office says the shooter arrested for killing Brii Jackson is a 14-year-old boy.
Students at the school are grieving the loss of Brii, who was murdered the day after her fifteenth birthday. Investigators say they're still trying to piece the motive together.
Brii's relatives say they had a great time last Friday celebrating her birthday. But less than 24 hours later, she laid dying just feet from her front door.
Relatives say the 14-year-old arrested for Brii's murder is a boy from the same mobile home park. They say the two had some kind of disagreement. A teen who says he witnessed the murder says the boy walked up to Brii, looked right at her and then shot her once in the chest.
"They were friends at one point. They've known each other for 6 or 7 years," said Tracie Addington, the victim's aunt. "It's heartbreaking, and I do not wish this on any other family."
The Dallas County Sheriff's Office is not releasing the suspect's information because he is a juvenile, and it's unclear where he got the gun.
Relatives say Brii was walking with her 14-year-old sister and a 10-year-old cousin when she was murdered. They say her sister held her as she lay bleeding in the street waiting for help.
Brii's relatives say she was a very smart, popular teenager who had a bright future. Right now, they are still in shock and trying to understand how another child could be responsible.