US man found guilty of leaving toddler son to die in hot SUV while he sexted teenage girl

'Today is not a day we consider a victory. It's not a verdict we celebrate', Cobb County District Attorney Vic Reynolds told reporters

Justin Ross Harris sits with his defence team in the Glynn County Courthouse in Brunswick, Georgia (John Carrington/Atlanta Journal-Constitution/AP)

A Georgia man whose toddler son died after being left for hours in a hot car was convicted of murder Monday by a jury that concluded a month's worth of trial testimony and evidence showed the father left his child to perish on purpose.

Since his trial began October 3, Justin Ross Harris had at times wept from his courtroom seat and once even grinned as jurors watched video clips of him with his son, Cooper. But Harris showed little emotion as the verdict was read Monday. The jury found him guilty on all eight criminal counts he faced, including malice murder.

“Today is not a day we consider a victory. It's not a verdict we celebrate,” Cobb County District Attorney Vic Reynolds told reporters outside the courthouse. He added: “I believe categorically, unequivocally, that justice was served today.”

The 22-month-old boy died after being left for hours in the back of Harris' SUV on June 18 2014. Harris said he forgot to drop his son off at day care that morning and drove straight to his job as a web developer for Home Depot, not realising Cooper was still in his car seat.

Harris told police he didn't notice Cooper until he left work for the day to go to a movie. The boy was dead, having sweltered in the car for about seven hours.

Soon afterward, investigators found evidence that Harris was having sexual relationships - both online banter and in-person affairs - with numerous women, including a prostitute and a teenager. Prosecutors charged Harris with malice murder, saying he intentionally killed his son in order to escape the responsibilities of family life.

Malice murder carries a sentence of life with or without the possibility of parole. Jurors also convicted Harris of felony murder, cruelty to children and other counts. The judge scheduled sentencing for December 5.

Defence attorneys insisted Harris loved his son and the death was a tragic accident. Maddox Kilgore, Harris' lead attorney, said he planned to appeal the verdict and also ask for a new trial.

“From the moment we met Ross Harris, we've never once wavered in our absolute belief that he's not guilty of what he's been convicted of,” Kilgore told reporters.

Harris never spoke of the verdict when his defence lawyers met with him in a holding cell afterward, Kilgore said.

Leanna Taylor listens to a question from defence attorney Maddox Kilgore during a murder trial for her ex-husband Justin Ross Harris who is accused of intentionally killing their son (John Bazemore/AP)

“Instead he recognised he can now begin the grieving process he's not been able to go through the last two-plus years,” Kilgore said. “He talked about Cooper and how much he misses him.”

Prosecutors ultimately prevailed with their argument that Harris must have known Cooper was in the car.

Harris drove less than two minutes to work after strapping the child into his car seat when they finished breakfast at a Chick-fil-A restaurant just over a half-mile from Harris' office. Parking lot surveillance video showed Harris also went to his car after lunch and tossed in some light bulbs he had purchased, though he never got inside. Detectives testified that Harris seemed too calm when answering their questions hours after his son died.

“It wasn't one thing that [jurors] said, 'This proves malice,”' lead prosecutor Chuck Boring told reporters. “It was everything.”

Jurors seen leaving the courthouse Monday declined to speak with reporters. Boring said he had spoken with some of them, and was told they were nearly unanimous when they began deliberations last week. He said they wanted to make sure and review the evidence, taking four days to deliver a verdict.

Prosecutors said Harris left online clues to murderous intentions. Evidence showed that minutes before Harris locked the car door on his boy, he sent an online message: “I love my son and all, but we both need escapes.” Five days earlier, Harris watched an online video in which a veterinarian sits inside a hot car to show it reaches 116 degrees in a half-hour.

Cooper Harris who died after being left in his father's car. (Facebook)

Defence attorneys said Harris was responsible for his son's death, but insisted it was an accident rather than a crime. Friends and family members testified he was a devoted and loving father, and the jury watched video clips of Harris trying to teach Cooper to say “banana” and letting the boy strum his guitar. The joyous moments had some jurors laughing aloud.

Harris' ex-wife, Leanna Taylor, also came to his defence. She divorced him in March and bitterly told the jury that Harris “destroyed my life.” But she testified he was a loving father who, regardless of how unhappy he may have been in their marriage, would not have harmed their son on purpose. Taylor was not in the courtroom on Monday. Harris was alone, except for his lawyers, as the verdict was read.

An attorney for Taylor, Lawrence Zimmerman, said they were disappointed in the verdict.

“Clearly it is our belief that this was not done with any malice,” Zimmerman said in an emailed statement.

Also testifying in Harris' defence was Gene Brewer, an Arizona State University psychology professor who specialises in memory and attention. He said it would have been possible for Harris to forget about Cooper in a matter of seconds.

Harris was also found guilty of sending sexual text messages to a teenage girl and asked for nude photos of her pubic area. The girl testified Harris knew she was in high school the months they swapped sexual banter when she was 16 and 17, and Harris several times sent her photos of his penis. He was asking for a photo of her breasts the day Cooper died.

Harris moved to Georgia from Tuscaloosa, Alabama, in 2012. He lived in the Atlanta suburb of Cobb County, which is also where Cooper died. Because of intense pretrial publicity surrounding the case, the judge agreed to relocate Harris' trial 275 miles away in the coastal port city of Brunswick.

AP