DALLAS (CBSDFW.COM) – Dallas police have arrested a 15-year-old who they believe is responsible for shooting and killing a clerk during a robbery at a Dollar General store on Monday.

Gabrielle Monique Simmons (courtesy of Simmons family)

READ MORE: North Texas, Miami (Ohio) Meet In Inaugural Frisco Football Classic

Investigators said Gabrielle Monique Simmons, 27, was fully compliant with the suspect during the robbery, handed over the money in her drawer and was still shot.

DPD said officers had dealt with the juvenile suspect in the past over family violence issues.

The announcement of the arrest came on the same evening the community hosted the victim’s family for a prayer service and fundraiser.

“It don’t seem real man. It’s not real. It can’t be real, it just can’t be real bro,” said Aris Joseph, the victim’s fiancé. “I didn’t expect him to be this young, but like I said, he didn’t have to shoot her.”

Simmon’s brother Christopher Simmons could not believe at first the age of the suspected gunman.

“When I first heard it, I was like, ‘Man he wasted his life.’ He also took a life, but also wasting a life,” said Christopher Simmons.

READ MORE: Gov. Abbott Attends State Capitol Menorah Lighting Ceremony In Austin

He and the rest of the family are most worried about the six kids Gabrielle Monique is leaving behind.

“A lot of grief they’re going to have to go through in life over something that could have been prevented,” said Christopher Simmons.

Joseph said the hardest part has been trying to explain everything to the children.

“I just told my kids we got to hold together, we’re going to stick together…forever,” said Joseph. “I’m not going to leave them; I’m not going to separate them or nothing like that. They ain’t got to worry about that.”

As for the teenager who is accused of killing the love of his life, Joseph had few words.

“He’s forgiven but not forgotten,” said Joseph. “Like she’s gone but not forgotten.”

MORE NEWS: 2021-22 Bowl Game Season Schedule Finalized

The family has set up a GoFundMe account to help pay for funeral costs and support the six kids who now do not have a mother.