A man accused of intentionally killing his toddler by leaving him in a hot car shed tears in the courtroom as jurors were shown 34 autopsy photos.

Ross Harris wept on Tuesday when former Cobb County Medical Examiner Brian Frist described the final hours of his son, Cooper, local news media outlets reported.

Frist testified that given the temperatures that day in June 2014, the toddler's death would have been "prolonged." He calls the death "agonizing."

"I believe he went through various stages as he was passing," Frist said. "He would've experienced nausea, a headache, dehydration, seizures, anxiety ."

A police officer testified last week that he smelled "the odor of death" emanating from the vehicle. Officers have said Harris would have noticed the smell immediately as he drove home from work with his dead son in a back seat.

Frist testified that he recalls a stale odor coming from Cooper's body, but not one of decomposition exactly.

"I don't think that type of smell was there. But when we get to 4 p.m. in the afternoon you'd have a stale odor of someone who had been breathing a long period of time, sweating a long period of time, gases released from GI tract, urinating."

Prosecutors said Harris intentionally killed 22-month-old Cooper by leaving him for hours in a vehicle parked outside his workplace. Harris's lawyers call the death accidental.

He faces life in prison if convicted of murder.

Harris moved from Tuscaloosa, Alabama to Georgia in 2012 to take a job with The Home Depot's corporate offices in Cobb County.

Pretrial publicity prompted the trial's move to Brunswick, 275 miles from the Atlanta suburbs.