Created: Fri, 11 Jul 2014 12:12:00 EST
Updated: Fri, 11 Jul 2014 06:09:40 EST
ATLANTA (CNN) -- Open a car door on a summer day, and a sauna blast will quickly remind you just how seethingly, sticky hot it can get inside in just a short time. It's suffocating.
For 22-month-old Cooper Harris, strapped all day into a child's seat in his father's SUV, as the sun baked it, it was fatal.
Investigators in Georgia wanted to know how high the temperature climbed in that back seat, so this week they recreated that sauna heat in Justin Ross Harris' silver Hyundai Tucson.
They drove it to the spot where it sat in the sun for seven hours on June 18, the day Cooper died.
They have not released the data yet, but CNN weather experts believe temperatures could have climbed to nearly 140 degrees inside the car.
The National Highway Traffic Safety Authority has corroborated the possibility.
"Even outside temperatures in the 60s can cause a car temperature to rise well above 110° F," the agency said.
The test came in the same week that the Cobb County medical examiner's office said toxicology tests on the boy revealed nothing abnormal, meaning he apparently was not drugged or medicated.
That report and the autopsy report -- which found the child's cause of death "consistent with hyperthermia" and that investigative information "suggests the manner of death is homicide" -- will not be released to the public until the investigation is complete, the office said Thursday.
Cooper's father, Justin Ross Harris, is charged with murder and child cruelty. He has pleaded not guilty.
Harris fired by employer
Harris, who worked for two years at the The Home Depot's corporate offices in the Atlanta suburb of Smyrna, has been terminated, a spokeswoman for the company said Thursday.
Harris, a web designer, had been on unpaid leave since charges were filed last month.
Catherine Woodling gave no details of the termination.
A Home Depot charity fund paid for Cooper's funeral.
Measuring temperatures at key times
During this week's car test, investigators parked in the same space that Harris did, WAGA reported, and measured the temperature at times of day that are key to the father's murder case:
-- At 9:30 a.m., when police say Harris pulled into the parking lot at The Home Depot's corporate offices. He normally would have taken Cooper to daycare then, but left him in the car.
-- At 12:42 p.m., when the 33-year-old father placed light bulbs he had purchased inside the car.
-- And at 4:16 p.m., when investigators say Harris drove off.
On the day Cooper died, the high temperature reached 92 degrees. Investigators used outside thermometers on Tuesday to monitor outdoor temperature rises.
Dozens of children die in hot cars every year, the NHTSA said.
People are in danger of dying of heatstroke when their body temperatures climb above 104 degrees and stay there for prolonged periods, according to the Mayo Clinic.
Heat attacks the brain, heart, kidneys and muscles, the Mayo Clinic said.
Victims can experience nausea and faintness, before organ damage sets in, eventually leading to death.
The elderly and small children are particularly susceptible to heatstroke.
Initially, police said the death of the toddler was the result of tragic absent-mindedness.
They said the dad had apparently forgotten the boy was in the back seat of his Hyundai Tucson and apparently didn't remember until he was done with his workday, drove a couple of miles and pulled into a shopping center parking lot.
But suspicions grew as police investigated, and Harris was charged.
Investigators also have unearthed uncomfortable details in Harris' online activities. He has performed Internet searches on child death in hot cars, they said.
While Cooper was left in the car, Harris was allegedly chatting via an online contact service with women. Police say that Harris, who is married, has, in the past, sent sexually explicit messages and photos on the service, including to an underage girl.
Leanna Harris, Justin's wife, has not been named a suspect in the case. Officer Michael Bowman, a Cobb County police spokesman, said Monday, "Leanna Harris has been interviewed. Detectives continue to work on the case."
Police have alleged she behaved strangely in the days before and moments after the death of her 22-month-old boy.
Thursday, defense attorney Lawrence Zimmerman confirmed to CNN he had been retained by Leanna Harris.
CNN"s Devon Sayers and John Murgatroyd contributed to this report.
(CNN) -- If you donated to a fund-raising campaign for the family of Cooper Harris, the suburban Atlanta toddler who died after being left in a hot car, you may soon be getting a refund.
YouCaring.com, the site where the fundraising effort was hosted, has taken the campaign down, and a spokesman for one of the two payment processing firms used in the effort, PayPal, said Friday that it will refund all of the contributions it handled.
The second firm, WePay.com, did not immediately respond to CNN's request for comment on its plans for donations it collected.
As of July 2, the effort had raised $22,677 of the $25,000 goal set by organizer Heather McCullar, according to a snapshot of the page maintained by Google. The page is no longer available on the YouCaring.com website.
"The campaign was recently removed from the site so that the controversy and debate surrounding the Harris matter did not become a distraction to the millions of other donors participating in a wide variety of active fundraisers currently taking place in our community," the company said in a statement.
It was not immediately known how much each service had collected, or if any of the money had reached the Harris family.
On June 21, Alabama Credit Union posted a note to its Facebook page saying donations were being funneled to an account there "owned by Ms. Harris to use purely at her own discretion -- but she clearly understands the intent of those donating to the fund."
The campaign was established after Cooper's father, Justin Ross Harris, was charged with murder and child cruelty in the June 18 death of his 22-month-old son.
But it was posted before revelations that he had searched for information about hot-car deaths or bombshell allegations in a probable cause hearing last week that he had visited a website dedicated to a child-free lifestyle.
A detective also said Harris was exchanging sexually explicit text messages with various women while his son was locked inside the sweltering car, painting a much different portrait of Harris than the dedicated and doting family man described by friends and family.
Harris has pleaded not guilty. In the preliminary hearing last week, Harris' attorney -- H. Maddox Kilgore -- said his client had tragically forgotten his child was in the car.
On Friday a second Georgia law enforcement agency said it is now inquiring about Justin Ross Harris' activities.
Woodstock Police Department has contacted Cobb County Police Department, "in regards to any alleged criminal activity within our jurisdiction," Public Information Officer Brittany Duncan said.
During the probable cause hearing, a detective with the Cobb County Police Department alleged Harris met one of the women with whom he exchanged explicit messages at Olde Rope Mill Park, in Woodstock.
"We have reached out to Cobb County and will coordinate with them on anything actionable," Duncan said. But at this point Woodstock Police say they don't have an active investigation.
During the probable cause hearing, July 3, Cobb County Police Sgt. Phil Stoddard testified that the department's preliminary investigation had revealed Harris had committed the computer-based crime of sexual exploitation of a minor. When asked if Harris had also committed two misdemeanor violations of illegal contact with a minor, sexually -- Stoddard agreed he had.
Calls to Harris' attorney, Maddox Kilgore, were not immediately returned.
CNN's Victor Blackwell and Devon Sayers contributed to this report.