CHICAGO (CBS) — A 7-year-old girl is dead and her 6-year-old sister was wounded in a shooting Sunday afternoon in the Belmont Central community.

SISTERS SHOT:  What We Know About The Case So Far

READ MORE: Ed's Tech Notes: Apple Cutting Production On iPhone 13, Twitter's New Feature, Drone Delivers Lungs For Transplant

The girls were identified by their grandmother as Serenity and Aubrey Broughton. Serenity died at the hospital, while Aubrey had been moved out of the ICU Sunday night – but had a pierced lung.

Serenity And Aubrey Broughton

Serenity (left) and Aubrey Broughton. (Supplied by Regina Broughton)

Chicago Police Chief of Patrol Brian McDermott said, at 2:50 p.m., police were called to the 6200 block of West Grand Avenue, at Merrimac Avenue, for a ShotSpotter alert.

At the scene, officers found the two little girls, who had suffered multiple gunshot wounds, in a vehicle parked on the street. The officers rendered first aid until Chicago Fire Department paramedics came and took the girls to the hospital.

Serenity was shot in the chest and torso, and was pronounced dead at Loyola University Medical Center in Maywood.

Aubrey was shot in the chest and right armpit, and was being treated at Loyola.

McDermott said the girls’ mother was getting them into the back seat of the car when the shots rang out.

As CBS 2’s Steven Graves reported, officers shut down Grand Avenue near the scene late Sunday afternoon.

Witnesses said they heard rapid gunfire at the time of the shooting. A man who lives across the street said he heard at least a dozen shots, and a lot of people said they heard screams from a woman when it happened.

Afterward, the witnesses came out to see the two girls being taken out of the vehicle. Both were lying on the ground, and one was unresponsive.

The girls’ paternal grandmother, Regina Broughton, said they had been coming from their maternal grandmother’s house when they were shot. The girls had been headed to see Broughton, who instead had to rush to the hospital – finding out Serenity did not make it.

“She was getting in a car coming from her grandma’s house, and her life was ended at that moment. I mean, that’s just senseless. And you know, someone should come forth and say something. Someone should come forth and help the family, and help us – because it didn’t have to happen to her. It shouldn’t have happened to her,” Broughton said. “She was innocent. She was 7. Her birthday was coming up in November.”

Broughton said Aubrey does not know her sister has died.

READ MORE: Chicago Weather: Warm Temps For The Bears Game

“She’s aware that she has been hurt,” Broughton said, “and she keeps saying it: ‘It’s not your fault, mommy. It’s not your fault.'”

Broughton said, when the shots flew out, her son – the girl’s father – was on the driver’s side of the car while their mother had just finished buckling Aubrey in.

“She heard what she thought was fireworks, and at that point, the little, youngest one was holding herself and fell on the seat,” Broughton said. “The other sister was already in her car seat buttoned up, and my son said he grabbed her – and she was just lifeless.”

Broughton said the shots came through the side of the door and struck the girls.

“How do you prepare yourself for something like this?” Broughton said. “She was a beautiful child. Her spirit was beautiful. Everything about her was innocent.”

Broughton said she was supposed to fly to South Carolina with the girls on Tuesday so they could visit Myrtle Beach. She said Serenity had been looking forward to her very first plane ride, and now she will never experience it.

“She had dreams of just going to the airport. She just wanted to see the airport; wanted to go up on a plane, and I arranged that for her – and didn’t even get to see it,” Broughton said.

Neighbors were also appalled at what happened.

“To see that this happened so close to my house – it’s very saddening. It’s kind of hard to take in, really,” said Manuel Gonzalez. “What if that happened to my younger siblings or relatives? I don’t know how I’d take it.”

McDermott said the girls were not believed to be the intended targets. He said there may have been more than one shooter, but there was not believed to be crossfire.

He said it was not known whether the shooters drove by or were on foot.

As of 7 p.m., detectives were still at the scene interviewing witnesses and canvassing the area, and also trying to find private video and recovering any and all evidence at the scene, McDermott said.

“To say that I am sad and outraged would be an understatement. I can only hope that every resident of the city is as angry, saddened, and outraged as I am at this time,” McDermott said at a Sunday evening news conference. “Too many young people have lost their lives to senseless gun violence in the city of Chicago.”

Broughton said the family is truly lost as to why such a horrific thing happened. Her son’s car had at least six bullet holes in it.

“Someone should come forth and say something. Someone should come forth and help the family,” Broughton said. “Help us, because it didn’t have to happen to her. It shouldn’t have happened to her. She was innocent.”

MORE NEWS: State Police Investigate Shooting On Kennedy Expressway Feeder Ramp

McDermott asked anyone who saw something to say something. Witnesses can go anonymously to CPDTIP.com.