Trial Begins for Georgia Dad Accused of Murder in Son's Hot-Car Death

— -- The murder case against a Georgia man whose 22-month-old son died when he was left in his father's hot SUV began today. The prosecution gave its opening statements, saying the father led a "double life" and his son got in the way of the life he wanted.

Justin Ross Harris' son, Cooper, died on June 18, 2014, after spending about seven hours in a rear-facing car seat in Harris' 2011 Hyundai Tucson in Atlanta, police said. That day, temperatures in the area reached the low 90s.

Authorities say Cooper was in the car when Harris drove to work at a Home Depot corporate office that morning, and when Harris went inside, Cooper was left in the vehicle. Harris returned to his car during lunch to put something away, then went back to work. Later that day, after Harris went back again to his car and drove away from work, he pulled over in a shopping center where he asked for help for Cooper, authorities say. Cooper -- who did not live to his 2nd birthday -- died from hypothermia.

Court documents show Harris allegedly researched child deaths in hot cars before he left his 22-month-old son locked in his SUV all day while he went to work. Charges in the indictment also relate to sexually explicit online exchanges prosecutors say Harris had with an underage girl from March 2014 through the day of Cooper’s death. Prosecutors say that Harris was having multiple online affairs, including with the underage girl, and argue that this shows he wanted to be free of his family.

Defense attorneys have said Cooper's death was an accident and that Harris forgot his son was in the car.

Harris, of the Atlanta suburb of Marietta, was indicted in Sept. 2014, on charges that include felony murder and cruelty to children. Because of pretrial publicity, the trial was moved nearly 300 miles away from Atlanta to the coastal Georgia city of Brunswick.

In opening statements today, Cobb County Assistant District Attorney Chuck Boring said Cooper "suffered horrible physical pain," adding that Harris "chose the worst imaginable death for his child."

Boring said Harris' behavior at the scene where Harris was pulled over and Cooper was recovered is strong evidence against him. Boring said when Harris jumped out of his car, he didn't ask for someone to call 911 -- he said, "What have I done?"

There were "no tears," the prosecutor said. Instead, he said Harris screamed and then was calm.

When Harris was put into the back of a police car, he didn't ask to see his son, Boring said, adding that Harris instead complained about it being hot in the back of the vehicle.

Boring said the motive is clear: that Harris, who he said was "very worried about perception," led a "double life" -- messaging teenage girls online and cheating on his wife -- and he wanted to remove the biggest obstacle to leading his double life -- his son.

Boring said one woman Harris met online in 2013 was an 18-year-old, adding that Harris, in his 30s, lied about his age and told the teenager he was 25.

Boring said Harris "was in love" with her, and that he once showed up at a Walmart in her hometown hours away to see her, where they sat in his car and kissed.

About three months before Cooper's death, "she started dating somebody and they kind of broke it off," Boring said, adding that Harris "was very upset about this." Harris was "despondent" that she wouldn't respond to him, said Boring.

Boring added that Harris' behavior was "escalating and spiraling out of control" leading up to Cooper’s death. The prosecutor claimed that Harris visited prostitutes and tried to begin relationships with teenagers. Boring said Harris "had numerous web searches for prostitutes," adding that during the trial the jury will hear from one prostitute with whom Harris allegedly had sex.

According to Boring, in a conversation with one woman, Harris told her that his conscience did not kick in when he cheated on his wife.

The defense will give its opening statements Tuesday morning, but Harris' attorney, Maddox Kilgore, downplayed the relevance of his client's sexual activity back in February, saying, "It's unrelated, uncharged, completely unconnected," according to People.

Harris faces eight charges total: Malice Murder, Felony Murder (two counts), Cruelty to Children in the First Degree, Cruelty to Children in the Second Degree, Criminal Attempt to Commit a Felony and Dissemination of Harmful Material to Minors (two counts). Harris has pleaded not guilty to all of the charges.

If convicted of all charges, Harris could face life in prison, according to the Cobb County District Attorney's office. A life term in Georgia is 30 years, unless the sentence is life without parole.

The Associated Press contributed to this report.