At about 7:30 p.m., Candice Dickerson, 36, was with her sons inside a MetroPCS store in the 5900 block of South Kedzie Avenue when she was hit by a stray bullet.
Officials say she was standing at the counter when a bullet came through the window and struck her in the back of the head.
WATCH: WOMAN'S SON WITNESSES HER FATAL SHOOTING
Dickerson, a pharmacy technician, was buying one of her sons a cellphone for getting a good grade on a project.
"She was trying to get down, but they shot her before she got down and she started bleeding," said her son Jacarey, 12, who was with his mother when she was shot. "I was scared."
He said his mother was crying and kept trying to get up until the ambulance arrived.
"I thought she was very brave. I thought that maybe she'd be able to survive, but when we got to the hospital, she did not survive," said Jacarey. ABC7 is not using the boy's last name.
Dickerson was taken to Advocate Christ Medical Center where she was pronounced dead.
Jacarey said his mother saying that even though she didn't have a lot of money, she tried to give them everything they needed.
"She was a good mom," he said.
Dickerson's three boys are staying with their grandparents.
Police said witnesses saw two unknown men on the corner firing shots. One of those bullets was the one that went through the window and killed Dickerson. An ambulance in the area was also struck by gunfire, police said.
The offenders ran away from the scene. No one was in custody late Saturday. Chicago police are investigating.
Barbara Alvarez was in the store just before the shooting.
"It's scary, now I'm like I can't believe that it happened to the lady," Alvarez said. "I mean she was right there next to me on my right side, her kids were right there sitting by the window minding their business, my son was with me too."