(CNN) -

As investigators in Georgia looked into the death of a 22-month-old boy left seven hours in a sweltering SUV, they seized computers from the father's office, a source with knowledge of the investigation told HLN's Nancy Grace.

The officers found something startling: an online search for information about how long it takes animals to die in hot cars, the source said.

It's unknown when the Internet search was conducted and whether the father did the searching. Police have declined comment when asked about the computer search.

The father, Justin Ross Harris, has pleaded not guilty to charges of murder and second-degree child cruelty.

He sits in jail without bond, with an appearance before a judge set for next Thursday. Police in Cobb County, just outside Atlanta, have been tight-lipped and haven't said whether what they found on the computer is one of the reasons they arrested Harris.

Father won't attend son's funeral

The funeral for Cooper Harris will be held Saturday in Tuscaloosa, Alabama. Justin Harris, 33, won't be allowed out of the Cobb County Jail to attend, sheriff's office spokeswoman Nancy Bodiford said.

The child's mother wanted to obtain photos of her son from the seized computers for use at the funeral but Cobb County police turned down her request, said Maddox Kilgore, the attorney for Harris.

Police spokesman Michael Bowman told CNN, "If we have evidence, we will not be releasing that due to chain of custody issues."

Bowman would not confirm what, if any, evidence they had in their possession.

A charity fund at Harris's employer, The Home Depot, will pay for the funeral, company spokeswoman Catherine Woodling told CNN. Harris, who worked as a web designer, has been placed on unpaid administrative leave, she said.

The funding of the funeral from the Home Depot charity, the Homer Fund, is a "standard approach," she said.

In an obituary for Cooper appearing in the Tuscaloosa News, the family asks that in lieu of flowers donations should be made to the Homer Fund.

'What have I done?'

Initially, police described the June 18 death of the toddler as the result of tragic absent-mindedness.

They said the dad had apparently forgotten the boy was in the back seat of his Hyundai Tucson; he didn't remember until he was done with his workday, drove a couple of miles and pulled into a shopping center parking lot.

But suspicions grew as police investigated.

"The chain of events that occurred in this case does not point toward simple negligence, and evidence will be presented to support this allegation," said Cobb County Police Chief John House.

A criminal warrant released Wednesday described the events that led to Cooper's death.

A timeline of events

On the day Cooper died, Harris stopped for breakfast at a fast-food restaurant and afterward strapped his son into a rear-facing child restraint seat on his SUV's back seat, police said.

He drove to his workplace, a Home Depot corporate office, about a half-mile away. He works as a Web designer there.

Usually, he would take his son to an on-site day care. But that day, police said, Harris left him in the car seat.

During his lunch break, he returned to his car, opening the driver's side door to put something inside, police said.

After work, around 4:16 p.m., the 33-year-old father got in his car and drove away. A few miles away, he stopped the car at a shopping center and called for help.