Justin Ross Harris was charged with murder on Thursday in the death of his 22-month-old son, Cooper, left in a hot car for hours in June.

A Cobb County, Georgia grand jury indicted Harris on eight charges, including felony murder, malice murder, cruelty to children, and underage sex crimes for texting a teen girl explicit photos.

Harris, 33, told police that on June 18, he was supposed to drop his son off at daycare but forgot. He drove to his job at a Home Depot corporate office, and left his SUV in the parking lot with Cooper still strapped into his rear-facing car seat.

When he got off work at 4:16 p.m., he drove a few miles before discovering his son. Authorities said he was inconsolable at the scene and screamed, "What have I done?" Cooper had been left in the car for seven hours, and the temperature reached 92 degrees that day in Atlanta.

Court testimony revealed that while Harris was at work, he was also sending nude photos to women and a teenager. He also texted explicit messages to the teen, and asked her to send him nude photos.

In addition, Harris previously researched prison survival on the internet, and watched videos of children dying in cars. Police also said that Harris' wife, and the mother of Cooper, Leanna, researched how hot a car would have to be for an unattended child to die. No charges have been brought against Leanna.

Cobb County Police Detective Phil Stoddard testified that "the evidence now is showing intent," at a July hearing, and despite police reports stating that Harris was distraught after discovering his son's body, Stoddard said there was drama, but no emotion.

"Harris is walking around, rubbing his eyes, look like he's trying to hyperventilate," he testified. "Then, nothing. No tears, no real emotion."

Harris has been held without bail since his son's death.