Pregnant mom is fatally shot in the back. Miraculously, her unborn baby survives.

Delashon Jefferson, 21, died Sunday in Dallas after sustaining a gunshot wound to the back. Jefferson, who was about eight months pregnant at the time, delivered a premature baby, who miraculously lived, in a cesarean section procedure.

What are the details?

On that fateful Sunday, Jefferson and her boyfriend, Lagarius Rainey, got into a heated argument, during which Rainey reportedly punched Jefferson. The blow led her to begin screaming. When Jefferson started screaming, her family came running into the couple's bedroom, where they argument had been taking place, and that's when Rainey reportedly snapped.

Jefferson's sister, LaJoyce Robertson, said that Rainey — who pleaded guilty twice before to aggravated assault against Jefferson — pulled out a gun and began firing.

“He ended up punching her in the face. She got to screaming,” Robertson said. Then she said Rainey "just started shooting everywhere."

Robertson was one of the people who entered the room, along with her fiancé, Daveron Sanders. According to police, Rainey's bullets struck Sanders twice in the chest. Sanders was taken to a nearby hospital and survived.

Jefferson, however, was not so lucky. She was also shot and collapsed in the hallway of her home as her mother comforted her.

Paramedics arrived on the scene and transported Jefferson to Baylor Medical Center, where she died.

What about the baby?

Jefferson's child, who was named after her mother, suffered several seizures due to oxygen deprivation but is still fighting for her life.

Robertson told KDFW-TV that though her sister is gone, the child is a "blessing."

“It’s a blessing. For her to still be here, to live through her mother,” Robertson said. “[We'll] tell her all about her mother. She just loved to smile, always quiet, never bothered anybody.”

Authorities said they discovered Rainey near the scene of the crime and reported that he admitted to shooting when Jefferson's family came into the room because he reportedly feared for his life.

Rainey has been charged with murder.