A 24-year-old Georgia man was charged with two counts of involuntary manslaughter in the deaths of his one-year-old twin daughters, who police say were left in a hot car. (Reuters)

When police pulled up to the low-slung apartment building in Carrollton, Ga., on Thursday evening, bystanders immediately waved the officers around to the back.

There, huddled over a kiddie pool filled with water and ice packs, they found Asa North.

In the pool lay his twin baby daughters, Ariel and Alaynah.

The girls were not moving.

North had left them in the back of his SUV, according to police. His desperate efforts to resuscitate them in the pool did not work.

Ariel and Alaynah, 15 months old, were pronounced dead at a local hospital.

North, 24, was arrested early Friday morning on two counts of involuntary manslaughter and two counts of reckless conduct, Fox 5 reported.

“We do believe they were left in the car for a period of time, ” Carrollton Police Capt. Chris Dobbs told CNN, referring to the twins.

Autopsies, to be conducted Friday morning, will determine how long that was — a detail that could be crucial in court.

RT @jleslie11alive #BREAKING – Asa North, 24, hangs head on way to jail for hot car deaths of twin girls #11Alive pic.twitter.com/v5FUobm8e4 — 11Alive News (@11AliveNews) August 5, 2016

At least 26 children have died from heatstroke this year after being left inside cars, according to a website that tracks such incidents. Cases of kids dying after being left in hot cars have risen since the late 1990s, when the advent of air bags and rear-facing child-seats pushed parents to put their kids in the back of the car, where they are more easily forgotten, experts say.

Temperatures inside a car can quickly rise to over 200 degrees, twice that required for heatstroke. A child’s body heats up three to five times faster than an adult’s, according to the Seattle Children’s Hospital.

In Carrollton, North’s neighbors rushed outside at around 6:30 p.m. Thursday when they heard screams, WTVM reported.

North took his daughters to the back of the complex where there was a kiddie pool, and neighbors tried to help by bringing ice packs. Someone called 911 to report that the twins were unresponsive. Authorities arrived, speeding the girls to Tanner Medical Center.

But it was too late. Ariel and Alaynah were dead.

[Forgetting a Child in the Backseat of a Car Is a Horrifying Mistake. Is It a Crime? — Gene Weingarten’s Pulitzer Prize-winning Post Magazine feature from 2009]

The girls’ mother was at an Atlanta hospital at the time of the incident, according to Fox 5. She was visiting a sister recovering from a serious car accident when she learned that her own daughters had died.

Police questioned Asa North on Thursday night before arresting him early Friday.

Local television crews captured the moment police led North out of the precinct and toward jail, his head bowed and his hands cuffed behind his back.

North is expected to appear in court on Friday.

[‘Blatant racism’ behind black father’s murder charge in toddler’s hot-car death, lawyer says]

“It’s so tragic. The commotion and everything outside has been a nightmare,” neighbor Holly Nelson told Fox 5. “I have two kids of my own and I can’t imagine losing them.”

Regina Cleveland, a friend of the North family, said that whatever happens to North, he has already paid a steep price.

“Only he knows the answer about what happened today, but I hope and pray it was an accident,” she told WSBTV. “There’s no reason for it, and I’m hoping that maybe he didn’t mean to do it because this is something he’s going to have to live with for the rest of his life.”

Read more:

As summer temperatures rise, here are a few simple tips from the National Safety Council to keep kids safe. (Tom LeGro/The Washington Post)

Two more children died over the weekend in hot cars. That’s 682 since 1998. It isn’t getting better.

Texas man tries in vain to save his infant left in hot car — by placing her in refrigerator

‘I left my 1-year-old baby in my SUV by accident,’ man tells emergency dispatchers