9 Investigates unsolved homicides in Central Florida

July marks two years since an Orlando couple was killed in front of their young son, but police have yet to make any arrests.

9 Investigates learned the case is one of hundreds of unsolved homicides in Central Florida, including some that are decades old.

Besides the pictures on the wall, Ray Collins has a constant reminder of his daughter--he's now raising her child.

He never expected to raise a child again.

“He's a blessing, but at the same time, it's under the wrong circumstances,” he said.

Orlando police said 26-year-old Renee Collins and her boyfriend, Piterson Delhomme, were slain in front of their 2-year-old son on Cinderlane Parkway in 2015. The boy wasn't hurt.

Detectives did not go into detail, but called the crime "brutal" and described the killer as "depraved."

“I'd like to get justice. I mean, someone did this. They need to be accountable for what they've done,” Collins said.

Two years later, there are still no arrests.

9 Investigates found out the homicides are among 170 unsolved murders in Orlando, with the oldest dating back to 1967.

When the unsolved cases go cold, the paperwork eventually ends up in a small room at police headquarters.

“Most of our cases are from the '80s and the '90s,” said Detective Michael Moreschi.

Moreschi said older cases become tougher to solve, as memories fade and witnesses die.

Police have used a federal grant to go back and test old evidence for DNA with some success, but he said most cases are solved with new technology or new information, and there's always a chance that could happen.

“I never promise a family that we're going to solve their case. But I tell them if the case doesn't get solved, it's not going to be due to a lack of effort,” Moreschi said.

Watch: The art of forensics

Collins holds out hope that his daughter’s killer will be found.

“I want closure. My family needs it. I need it,” he said.

Police said the case remains open but they have no new leads.

St. Petersburg has a similar population to Orlando, with 226 unsolved homicides piled up.

Tampa, which is larger than Orlando, has about 400.

Orange County has 473 open cases, with the oldest dating back to 1941.

Cox Media Group