DURHAM, NC (WTVD) -- Durham Police suspect there may be a financial motive in the death investigation of William Bishop.
On the evening of April 18, Bishop's teenage son told the operator he found his father slumped in a chair with a dog leash wrapped around his neck, with their dog still attached.
Caller: When I got in there and checked his pulse. He wasn't breathing. His heart wasn't beating.
Operator: Is there anyone else at the home with you?
Caller: No. (pause) I don't know if I can go in there again. I don't want to look at him.
Operator: I understand sir.
After Durham Police arrived at their home in the 3400 block of Dover Road, investigators said the boy claimed his father was verbally abusive and he would not be upset if Bishop did not survive.
A few days later, the 59-year-old UNC PhD student and developer died.
A preliminary autopsy suggests he was strangled.
Right now, Bishop's son is part of the death investigation.
Through newly released court documents, detectives are looking for evidence in William Bishop's home safe, after discovering a receipt in his office for 25 pieces of gold valued around $463,000.
Earlier this month, a loved one told authorities he kept gold, jewelry and cash in a safe.
Police then got a search warrant to try to get inside that safe.
Last month, police went to Durham Academy, where the boy attended school, to search his emails.
Warrants said a forensic team also went through the child's iPhone, and found suspicious activity, including searches on how to calculate the value of an estate, how to transfer bank accounts, and the value of the price of gold per ounce.
It's a disturbing detail that Bishop's girlfriend, Julie Seel, is reluctant to talk about.
Instead, she is focusing on how he lived.
Seel told ABC11 the couple's whirlwind romance lasted one year before its abrupt end.
"I continue to be utterly devastated. Nothing makes sense without Bill. He was part of everything, now everything is in parts. He is simply the greatest man I have ever known and exactly the type of father I always wanted for my daughter," said Seel.
Bishop's son has hired a new attorney.
His attorney was not available for comment.
Durham police suspect financial motive in UNC PhD students death