Murder trial begins for dad who left his son in a hot car all day.

Jury selection has begun for the trial of a man accused of murdering his 22-month-old son after he left him in a hot car all day while at work.

Justin Ross Harris, says he was driving home from his office one night in June 2014, when he first noticed his young son Cooper sitting in the back-seat.

It was at that moment that Harris claims he realised he had forgotten to drop his son off at day-care that morning, and that his son had been sitting in the back-seat of the car for seven hours.

This action, whether accident or purposeful, ultimately led to Cooper’s death.

The case has captivated attention in Harris’ home state of Georgia in the United States, and around the world.

Cooper Harris before his untimely death. Source: Youtube.

Now, almost two years after Cooper's death, selection has begun for the jury that will ultimately decide Harris' fate.

While Harris' defense attorney is claiming that it was a terrible and tragic case of fatal distraction on the accused's part, the prosecution has evidence that tells a more chilling story.

Police investigating the case found that prior to Cooper's death, Harris had taken out two life insurance policies for his son, Googled "how to survive in prison" as well as information on temperatures inside cars, and more disturbingly, child pornography on his personal computers.

Justin Harris with his son Cooper. Source: Youtube. 

It was also found that Cooper had been texting multiple women in the time leading up to and on the day of Cooper's death.

It is believed by some that Harris murdered his son in order to live a child-free lifestyle with younger women.

Harris and his then-wife Leanna, who was also Cooper's mother, have since divorced.

Justin Harris appearing in court. Source: Youtube.

Harris' freedom now rests in the hands of 12 unknown individuals, so choosing the right jury for the high profile case is paramount.

As such, the court is asking potential jurors to complete a 17-page court approved questionnaire to gauge their opinions on sex, pornography, relationships and other key information surrounding their day-to-day lives.

Questions range from the seemingly benign, "Have you watched any legal documentaries or docudramas?" and "Do you have a child that rides in a car seat?" to the more personal, "Have you ever had an extramarital affair?" and "Have you looked at a pornographic website?"

So far 250 potential jurors have completed the questionnaires, with more expected in the coming days.

Jury selection is set to continue throughout next week.