The girl's grandmother, Dana Sweatt, confirmed to Channel 2 that 15-year-old Precious Alex died after an unknown gunman opened fire through the window of a basement apartment around 3:30 a.m. Tuesday.

"She's dead," Sweatt cried. "She's only 15 years old!"

Sweatt described her granddaughter as an honor roll student who was planning to return with her to Fairbanks in the coming months. She was in town to take her high school exit exam. Sweatt said she was a student at Lathrop High School in Fairbanks.

Sweatt said Alex was shot in her side in a room full of family members.

"Senseless," she said, shaking her head as she cried. "Senseless. Senseless."

Anchorage police responded to the shooting at 633 North Flower Street, near the intersection of N. Flower and Parsons Ave. 

At least five bullet holes were visible through the apartment's window. The grandmother said the apartment belonged to Alex's mother.

Alex was taken to a local hospital with life-threatening injuries, but at 8:52 a.m. police said she had died. Her family has been notified.

Police had the entrance to the basement apartment taped off as they investigated the scene.

APD spokesperson Jennifer Castro confirmed that "multiple witnesses (were) in custody" following the shooting.

No information was available as to a possible suspect or motive.

For Sweatt, it was the second time she had lost a child in her family in the last year.

"Just last June I buried my niece," she sobbed, breathless. "Citari Townes-Sweatt ... and now I'm going to bury my granddaughter."

Townes-Sweatt was 20 years old when she was killed by an alleged drunk driver in June 2013. JBER airman Lane Douglas Wyatt, 22, has been arrested in connection with her death.

KTUU's Corey Allen-Young contributed to this story. 

This is a developing story. Watch Channel 2 broadcasts and check for updates.