ARLINGTON -- After hours of questioning, a woman has been released from custody after she shot and killed her fiancé in self defense, Arlington police say.

Police say the 27-year-old woman had injuries consistent with domestic violence, and there were other witnesses in the home. They also said the man, age 33, had a history of domestic violence calls against him in Mansfield.

The fiancé has been identified by his family as 32-year-old Isaac Flores, a father of five and Marine veteran.

His sister, Lorena Canales, spoke to WFAA about him while holding back tears.

“He was always smiling and laughing," she said. "And he was very happy to be with this woman because he said she changed his life for the better."

But police paint a different picture. Harrison says Flores had a history of domestic violence with his 27-year-old fiancée. Police won’t get into specifics, but say they have evidence it had happened again before Thursday’s shooting, saying the woman was hurt.

At this point, the woman has not been arrested, but the district attorney will review the case.

“I can tell you that we do firmly believe she was victimized,” Harrison said, “and we didn’t want to further victimize her.”

Just before 3:30 a.m. Thursday, the woman called police and told them she shot her fiancé, said Arlington Police Sgt. VaNessa Harrison.

Police arrived to the home on the 1300 block of Cloyne Drive and found a man dead inside the bedroom.

Family members say the couple had three children inside the home. According to police, the children had been staying with family since the shooting.

Flores’ nephew, Christian Canales, and Canales’ girlfriend, Luisa Quintana, had been living with the couple in their south Arlington home for months. They say the couple seemed “happy” and that they never witnessed any violence.

Both Canales and Quintana were home when the shooting happened but said they heard nothing before or after the incident.

“It was just silence," Quintana said. "I mean, it was a loud thump, no screaming, no yelling, nothing."

Canales says Flores, her younger brother, had PTSD from his service in the Marines, but had gotten things under control. She says none of this makes sense.

“I just want everyone to know, you know, he wasn’t perfect, but he didn’t deserve to die,” she said. “Nobody deserves to die.”

Neighbors said they never noticed signs of problems at the home in the past, but the couple had recently moved there.

WFAA attempted to talk with Flores’ fiancée Thursday but were told she would not be speaking. WFAA isn't releasing her identity at this time because she hasn't been charged.

No charges have been filed at this time. Police will turn the findings of their investigation over to the district attorney's office.