John Ramsey talks about his raw emotions on December 26, 1996, the day he found the body of his 6-year-old daughter, JonBenét Ramseyin the basement of the family’s home in Boulder, Colorado.

“When I found JonBenét, there were no tears,” Ramsey told PEOPLE in an exclusive interview. “Well, I lost my oldest daughter in a car accident a few years ago, and when I got that call, I was angry. I was angry. I was shocked. I didn’t cry. I cried for years after that, but in that moment you’re in shock. I was angry. I was angry with God.

He adds: “At least for me. If I were on a business trip on a plane, sitting alone, I would start crying every couple of years. It’s the weight of the loss, but at that moment, you’re in shock.

Earlier that morning, John’s wife Patsy called the police after noticing their daughter missing. During the call, Patsy, who has since died, frantically revealed that she had discovered a chilling ransom note demanding $118,000 for JonBenét’s safe return.

After John found JonBenét’s body, it was revealed that she had been sexually assaulted and strangled in their home. The queen of the children’s beauty pageant had duct tape over his mouth and a tourniquet wrapped around his neck.

His death was ruled a homicide and the parents quickly became suspects — which Ramsey said happened because of the parents’ initial reactions.

To learn more about John Ramsey’s fight to have JonBenét’s murder solved in his lifetime, subscribe now to PEOPLE or pick up the new issue of People, on newsstands next week.

“We didn’t do the right thing that morning, so they’re guilty,” Ramsey says of what investigators believed. “And that’s just incompetence.”

No member of the Ramsey family has ever been charged in connection with JonBenét’s murder. Patsy died in 2006.

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Nearly 30 years later, the case remains unsolved. Now, Ramsey hopes to encourage someone to come forward with new information and “put pressure” on police to use advances in DNA technology and genetic genealogy to finally catch her killer. JonBenet.

Ramsey also speaks in Netflix’s three-part docuseries, Cold Case: who killed JonBenét Ramsey?which begins broadcast on Monday, November 25.

The series explores what Ramsey sees as missteps made by authorities during the investigation into JonBenét’s murder amid an international media frenzy.