Their granddaughter and her friend were killed 4 years ago. This is how they want you to help catch the killer

When the teens failed to meet Libby’s dad that afternoon for a ride home, a massive search began. Eighteen hours later, the bodies of Libby and Abby were found in the woods, not far from the abandoned railroad bridge they’d been photographing during their hike on the Delphi Historic Trails.

It was another image Libby captured that caused the case drew headlines across America — a grainy, pixelated blur of a man in a blue jacket and jeans on the bridge. Police believe that man killed the girls.

The image changed the streets of Delphi and continues haunting families across Carroll County. The photo was plastered all over the world.

Four years after the tragic and senseless crime, the killer remains at large and police believe he may be living in Delphi — walking its streets, working, and hiding in plain sight.

The people of Delphi have tried to move forward. But the classroom desks Abby and Libby once occupied are among the constant reminders of the void left by the alleged actions of the man on that bridge.

Grandparents desperate for answers

Libby’s grandparents, Mike and Becky Patty, have devoted themselves to getting the haunting image of the man known as “Bridge Guy” in front of as many eyes as they can.

Someone knows who the man is and the couple are hopeful that someone will eventually provide that final tip that law enforcement says is needed.

HLN asked the grandparents to write a letter to the public about the case and their quest for justice. In their own…