Jury selection began on Monday at the Cobb County Courthouse in Marietta, Georgia, as attorneys from both sides began the arduous process of culling the 550 potential jurors down to 12.
On the June 14, 2014 day Harris allegedly left his son, Cooper, in the family's SUV, the outside temperatures were nearly 90 degrees. An autopsy found that Cooper died of hyperthermia.
Harris's attorney, Maddox Kilgore, contends that Harris merely forgot about Cooper because he was distracted, and that Harris never intended to harm his son.
Prosecutors charged Harris with eight felony counts, including malice murder, cruelty to children and criminal attempt to commit a felony.
Alleged Sexting and Strange BehaviorProsecutors contend that Harris was not the loving father he claimed to be.
In a pretrial hearing, a detective told the court that Harris had exchanged sexual text messages with six different females while his son was dying in the car. One of the females he allegedly sexted was just 16 years old.
In a 2014 probable cause hearing, detective Phil Stoddard outlined Harris's alleged strange behavior, both before and after Cooper's death.
According to Stoddard, Harris had researched hot car deaths online. He also searched "how to survive in prison."
Surveillance video had shown Harris returning to the car during lunchtime and placing two boxes of light bulbs inside. He didn't look at Cooper's car seat.
Stoddard also testified that Harris grew belligerent with responding officers after discovering Cooper's lifeless body. When he was arrested, Harris allegedly said, "But there was no malicious intent."
Will His Wife Testify?For nearly two years, Harris's wife, Leanna, has stood by him, calling him a good father.
Earlier this year, however, she quietly filed for divorce.
She is on the trial's witness list, but it's unclear whether she will be called to testify against or for him.
The trial is expected to last several weeks. Harris faces life in prison if he's found guilty.