CHICAGO (CBS) — Three months after she testified against the man ultimately convicted of killing her cousin, 18-year-old Treja Kelly was gunned down while walking home around the corner from where her cousin was shot in Chicago’s Back of the Yards neighborhood.

Police said Kelly, who was pregnant, was walking near 52nd and Peoria around 9:30 p.m. Sunday, when a man walked up from an alley, and the two of them got into an argument.

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The man then pulled out a gun and shot her several times in the head and chest.

Kelly was taken to the University of Chicago Medical Center where she was pronounced dead, according to police and the Cook County Medical Examiner’s office.

Police said they have not yet determined a motive for the shooting, but the Cook County State’s Attorney’s office confirmed Kelly testified at the trial of 30-year-old Deonte Davis, who was accused of killing her 17-year-old cousin, Christopher Fields, in 2016. The trial ended in Davis’ conviction.

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Authorities have said Davis shot Fields, an Urban Prep Academy student, near 52nd and Sangamon on June 11, 2016. Police and prosecutors said Fields had met his cousin that day and offered to walk her home and shielded her from gunfire during the shooting.

With Kelly’s slaying, her grandmother has now lost three grandchildren to gun violence.

“My grandchildren are very dear to me, and I’m losing them,” Judy Fields said.

Despite the pain of knowing she will never see her granddaugher again, Fields said she’s trying to stay strong for Kelly’s mother and two siblings.

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“You just have to pray about it and ask God to give you strength.”