(CNN) -

The suspect in a Georgia toddler's death told police he used the Internet to research child deaths inside vehicles, a search warrant said.

The father, Justin Ross Harris, 33, has pleaded not guilty to charges of murder and second-degree child cruelty in the death of his 22-month-old son, Cooper Harris. The boy died after he was left seven hours in a sweltering SUV on June 18.

"During an interview with Justin, he stated that he recently researched, through the Internet, child deaths inside vehicles and what temperature it needs to be for that to occur," according to a sworn statement in the warrant from a police officer. "Justin stated that he was fearful that this could happen."

According to search warrants from a Cobb County magistrate court, investigators seized a number of items from the father's home: An iPhone 5, Hyundai car, home laptop computer, computer tower, a "Google chrome cast Internet searcher" and other electronic devices.

Cobb County Police said the purpose of the search warrants was to find blood, DNA, writings and photographs relating to child abuse, child neglect, homicide to children and cruelty to children.

Harris sits in jail without bond, with an appearance before a judge set for next Thursday. Police in Cobb County, part of metro 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 calls in to son's funeral

Though Harris wasn't allowed out of the Cobb County Jail to attend his son's funeral on Saturday in Tuscaloosa, Alabama, he called in and spoke to the entire auditorium on speakerphone.

"Thank you for everything you've done for my boy," he said. "Good life. (Inaudible) No words to say. Just horrible. (Inaudible) I'm just sorry I can't be there." "

He told everyone he loved them and started crying again.

The child's mother had wanted to obtain photos of her son from 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' 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 newspaper, the family asks that in lieu of flowers donations should be made to the Homer Fund.

'What have I done?'

Initially, police described the 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.