Tips led to the arrest of a 15-year-old boy on Thursday for the shooting death of a Dollar General store cashier in Oak Cliff.
Gabrielle Monique Simmons, a 27-year-old mother of six, was shot to death on Monday at the store, which is located in the 4800 block of Sunnyvale Street.
Authorities have not released the boy's name since he is a juvenile.
"I'm just happy they caught him. I didn't expect him to be this young. But he didn't have to shoot," said Aris Joseph, 30, Simmons' fiance.
Simmons gave the robber cash from her register but the teenager still shot her in the chest, police said.
"We've handled him before for a violence offense," said Deputy Chief Malik Aziz during a news conference on Thursday.
Aziz didn't release further details on the previous offense but said it was family-related.
"I'll say this, by far we have more youth doing the right thing than youth doing the wrong things," said Aziz about the suspect's young age "... But we want to engage [the youth] and steer them away from this kind of life because today not just Gabrielle Simmons and her family's lives have been destroyed; the life of a 15-year-old kid has been destroyed, as well as his family."
The deputy said the suspect was taken into custody by a task force unit just north of the shooting and booked into the Dallas Youth Operations Unit.
On Thursday night, Aris Joseph, who unloads trucks at a furniture store in Carrollton, took his children to church where the community gathered to offer them support and encouragement.
"I've been with her for 11 years. I've been taking care of all these kids since they were born. It's going to get rough, it's going to get hard. I can do this. I can do it," he added. "My biggest concern is their comfort and the way they feel. They need that shoulder to lean on. They need more than just that shoulder, they need me. Just like I need them. I need them to be strong for me, and I gotta be strong for them."