(CNN) -

What sounded like the most tragic of accidents -- a dad absentmindedly leaving his toddler in the car on a scorching Georgia day -- is now being treated by police as a horrific crime.

Two new details were added to a revised Cobb County criminal warrant Tuesday: Not only did Justin Ross Harris put his son in the car minutes before arriving at work on June 18, but he also returned to his car hours later during his lunch break.

Harris placed his son, 22-month-old Cooper, into a rear-facing child restraint in the backseat of his Hyundai Tucson after eating breakfast at a fast-food restaurant. He then drove to his workplace, a Home Depot corporate office about a half-mile away, according to the warrant.

The 33-year-old father returned to the car during his lunch break, opening the driver's side door "to place an object into the vehicle," the warrant states.

Later that afternoon, around 4:16, Harris left his workplace near Vinings, outside Atlanta. Within minutes, he pulled into a shopping center asking for assistance with the toddler, who had been in the car for about seven hours at that point, the warrant says.

Did Harris intend to kill his son?

Besides felony murder, Harris was charged June 19 with first-degree child cruelty.

On Tuesday a magistrate judge downgraded the lesser charge to second-degree child cruelty.

Mark Gargaros, a CNN legal analyst, offered this interpretation of the downgrading of that charge Wednesday on "Anderson Cooper 360."

"It's almost a concession that they don't believe, that the prosecutors don't believe they've got the evidence to say this is intended or premeditated," he said.

The second-degree warrant says Harris "did with criminal negligence causes (sic) a child under the age of 18 cruel or excessive physical or mental pain."

The earlier, first-degree child cruelty warrant said the crime occurs when a person "willfully deprives the child of necessary sustenance to the extent that the child's health or well-being is jeopardized. ..."

"There's a difference between negligence and gross negligence," Cobb Police spokesman Mike Bowman said at a press conference. "The thing about the negligence is that it could happen to anybody. The gross negligence shows that there's some other circumstances revolving around this."

When a reporter directly asked if authorities think it's malice or negligence, Bowman said, "I honestly don't have an answer for that question."

But in a seeming contradiction of the charge being downgraded, Cobb County Police Chief John House said Wednesday in a press release, "The chain of events that occurred in this case does not point toward simple negligence and evidence will be presented to support this allegation."

'A distressed moment'

Witness Dale Hamilton told CNN affiliate WSB-TV that an emotional Harris pulled into the shopping center after purportedly realizing he had forgotten to drop Cooper off at day care at 8:30 a.m. The day care is reportedly located at the Home Depot office where Harris works.

"Laid his son on the ground, started doing CPR trying to resuscitate him. Apparently the child wasn't responding," Hamilton told the station.

Police saw a crowd, and when officers began to investigate, they saw the child on the ground. Once it became clear that Cooper was dead, Harris had to be physically restrained, police said.

"There were a number of witnesses -- passers-by in the area who observed basically the father in a very distressed moment," said Sgt. Dana Pierce of the Cobb County police.

Added Hamilton, "He kept saying, 'What have I done? What have I done?' And that's all that I could ascertain that he was saying."

Medical examiner opinion

Police seemed sympathetic at first, and Pierce told media that Harris apparently forgot the child was in the back of the vehicle while he was at work.

The average temperature was about 80 degrees that day, but the mercury topped 92 at the hottest point in the day. Police say the temperature was 88 degrees when the child was pronounced dead at the scene.

The child's cause of death was "consistent with hyperthermia and the investigative information suggests the manner of death is homicide," the Cobb County Medical Examiner's Office said, according to a Cobb County Department of Public Safety release issued Wednesday.