CHESTERFIELD COUNTY, Va. -- Chesterfield Police are investigating after responding to a report of two children left in an unlocked and running vehicle on one of the hottest days of the year.

The 911 call was placed from the parking lot of the Walmart at Hancock Village on Hancock Village Street just before noon Friday.

Brandy Andrews said she first heard a passerby frantically yelling for help while pulling into the shopping center.

"She was screaming, 'There's babies in the car, there's babies in the car!" Andrews recalled.

Andrews said she could see two young boys buckled in the backseat. The boys appeared to be less than two years old.

"There's a heat advisory today and the car is parked in the sun," she described. "They're not in a shaded area and you can see them visible in the window crying."

Friday afternoon high temperatures reached in the upper 90s. A heat advisory was in effect for much of central and eastern Virginia, which means the heat index rose to 105° or hotter.

"They're sitting unattended and forward-facing at their age," Andrews explained. "My heart broke."

Photos taken by witnesses show the Good Samaritans holding the boys until police arrived. One photo showed a purse was also left in the front passenger seat.

They estimated it took approximately 15 to 20 minutes for the boy's caregiver to arrive at the car after shopping.

"A woman appeared not in distress, very nonchalant and didn't understand what was going on," Andrews said.

Andrews, who has three children of her own, feared the "what-ifs" in the Walmart parking lot.

"The purse that was left in the front seat -- what if someone sees that and decides to jump in the car. The car was unlocked and I got into it without any problem. All I had to do was open the door," she said.

Witnesses said paramedics checked the children out at the scene.

Chesterfield Police said the boys are OK. No word if anyone has been charged.

Brendan King was later told the boys were with their nanny, who he said had been fired.

This is a developing story, so anyone with more information can submit a news tip here.