ATLANTA (CNN) -

It's a tragedy that has made many people across the country sick to their stomachs. A Georgia father said he drove to his job in suburban Atlanta June 18, parked and worked a full day only to return to his car and find that he'd forgotten that his infant son was in the back. Cooper, 22 months, was dead. Temperatures that day had soared to 92 degrees.

There have been a lot of twists and turns in the case involving Justin Ross Harris, who is facing murder and child cruelty charges. The 33-year-old has pleaded not guilty. At a hearing July 3, one of the story's most sensational details emerged: the prosecution's lead investigator testified that while Harris was at work and his son was dying in the car, the father sent explicit messages and exchanged texts with six women. Harris also sent a picture of an erect penis to an underage female, Cobb County Police Detective Phil Stoddard testified.

Cobb County Chief Magistrate Frank Cox denied bond for Harris and ruled that there was sufficient evidence to move forward in the legal process.

So what does that mean exactly? Where is this drama headed, what's happening with Leanna Harris, Cooper's mother, and what have we learned so far?

Testing on Harris' car and toxicology testing on Cooper

On Tuesday, CNN affiliate WXIA reported that investigators returned to Ross Harris' job location to recreate the conditions of the day that Cooper died.

Cobb County Police spokesman Michael Bowman told CNN that the department "turned over" Harris' vehicle that morning to the Cobb County District Attorney's Office for "heat testing" and it was returned Tuesday evening. No Cobb County police officers were at the scene when the testing happened, Bowman said, and the results of test will stay with the district attorney's office.

Bowman also told CNN Wednesday that a toxicology test was administered on Cooper's body, but those results are not yet available.

While the temperature on the day Cooper died was around 92 degrees, CNN weather experts believe temperatures could have climbed to nearly 140 degrees inside the car.

New documents released this week

Documents released Monday revealed more details of the investigation.

The documents, which included applications for search warrants and eight actual search warrants in the case against Harris, seek the medical records of Ross Harris and his son, a DVD, a 2-gigabyte memory card, a 32GB thumb drive and an external hard drive.

According to Stoddard, before Cooper Harris' death, the boy's father visited a Reddit page called "child-free" and read four articles; he allegedly searched online about how to survive in prison and how hot a car needs to be to kill a child. It wasn't clear from Stoddard's testimony exactly when these searches took place.

When does a grand jury come in?

Investigators continue to search through evidence and conduct interviews.

When they're done, law enforcement will hand over its findings to the prosecutor's office, which will present the case to a grand jury. Sources tell CNN that it may be late July before the grand jury makes a decision.

Cobb County District Attorney's Office spokeswoman Kim Isaza told CNN Wednesday that ethical standards bar the prosecutor's office from commenting on evidence in the case. "This case will run its course and we will follow wherever the evidence leads us," she said.

What about Cooper's mother?

On Tuesday, Leanna Harris, who has not been named as a suspect in her son's death, visited her husband at the Cobb County Jail, according to CNN affiliate WXIA.

It's unclear whether she was able to talk to him.

Citing the ongoing investigation, Cobb County Sheriff spokeswoman Nancy Bodiford told CNN the department wouldn't release details about any visitors Ross Harris has. Bodiford also said the department would not release audio of phone calls Harris receives or describe conditions of his confinement.

Couple is being closely watched

Any communication the couple has at the jail will be recorded, Atlanta attorney Page Pate said on CNN Wednesday. Page is not associated with the case.

On Thursday, Cobb County attorney Lawrence Zimmerman told CNN that Leanna Harris has hired him, adding that he is not speaking to the media at this time.

There's not much publicly known about his client. The 30-year-old dietitian is licensed in Georgia and Alabama, records show, and she has lived in Georgia since 2012. Before moving to the Atlanta suburb of Marietta, Leanna Harris lived in Moundville, Alabama, a town of about 2,400 people south of Tuscaloosa.