"Through the investigation, Harris has made comments to family members regarding a life insurance policy that he has on Cooper and what they need to do in order to file for it," says a June 24 search warrant obtained by PEOPLE.
During Thursday's court hearing, Cobb County Detective Phil Stoddard testified that the Harris family had two life insurance policies for their son – one for $25,000 and another for $2,000. The toddler's funeral was sponsored through a grant from Home Depot, where Harris worked.
Harris told detectives that he had about $4,000 in credit card debt, as well as outstanding student loans and car loans on two vehicles.
There have been at least 16 search warrants issued in the case. In warrants for the family's phones, iPad and computers, investigators are focusing on the family's finances and debt, as well as life insurance policies. In one warrant for the family computer, investigators are searching for "emails regarding child, wife and family issues, photos/videos of the child to show development, information about car seat searches, and searches regarding car deaths." Police are investigating whether there were marital problems between Harris and his wife, Leanna. They allege that Harris sent explicit texts to six recipients – including a teenage girl – on the day his son died.
Detectives are also searching Cooper's medical records to find out about any pre-existing medical conditions, as well as details of his growth and development.
In the search warrants, police say that both Ross and Leanna Harris claimed that their biggest fear was leaving Cooper in a hot car. "According to Harris," says one of the warrants, "he recently viewed a television show concerning child deaths in cars. During the interview with Leanna, she also made a similar statement that this was her worst fear."
"Investigators questioned her further about this," says the search warrant. "Leanna stated specifically that her fear was that her child would be left in a hot vehicle, not the fear of losing a child."
Justin Ross Harris is being held without bond on charges of murder and child cruelty. He has pleaded not guilty, and his attorney, Maddox Kilgore, has called the death a "tragic accident." Leanna Harris has not been charged.
Reporting by POLLY POWERS STRAMM