Police investigating the death of an Atlanta toddler allegedly left alone for seven hours in a hot car by his father on June 18 have raised the possibility that the tragedy may not have been an accident, UK MailOnline reported.

Justin Ross Harris, 33, of Marietta, was supposed to drop his toddler, identified in reports as Cooper, at a daycare center around 9 a.m. Wednesday morning on his way to work. But Harris drove straight to work, apparently forgetting that his son was strapped in his car seat in the back of the vehicle, Cobb County Police spokesman Dana Pierce said.

Although Harris has been charged and arrested for felony murder and child cruelty in the first degree, inconsistencies in his story has led police officials to question the Home Depot employee's version of events. "Much has changed about the circumstances leading up to the death of this 22-month-old since it was first reported," Pierce told CNN.

"I've been in law enforcement for 34 years. What I know about this case shocks my conscience as a police officer, a father and a grandfather. Within moments of the first responders getting to the scene and doing their job and questions began to be asked about the moments that led up to their arrival at the scene, some of those answers were not making sense to the first responders."

An autopsy conducted on Cooper should answer some questions for Cobb County police, including whether the information the child's father gave police is accurate. But police said Monday the autopsy report is not ready to be released, and it's not known when it will be available.

It wasn't until Harris was driving back home at 4 p.m., that he noticed Cooper's lifeless body in the back seat. Temperatures in the Atlanta area had reached 92 degrees F (33 C) on Wednesday, according to the National Weather Service.

Immediately pulling over the SUV at the Akers Mill Square shopping center on Cobb Parkway, Harris tried to perform CPR on Cooper.

A witness described watching the distraught father pull the child out of the car and attempt to resuscitate him, Dale Hamilton told CBS46."He was constantly saying, 'What have I done, what have I done?'" Hamilton said.

The child was discovered by police as they were patrolling the area on Wednesday afternoon and saw a crowd gathered in a shopping center parking lot. Harris had to be restrained at the scene because he was so upset. "As officers began to render medical treatment to the 22-month old male child, it was discovered that he was deceased after apparently being left unattended in his car seat inside the vehicle," a police statement said.

On Thursday, Harris pleaded not guilty to felony murder and cruelty to children charges. He's being held without bond at the Cobb County Jail.