DELPHI — A relatively new cable TV series with a world-renown crime-fighting host will soon place the national spotlight on the still-unsolved February 2017 homicides of two Delphi teenage girls.

“In Pursuit with John Walsh,” on the popular crime-show Investigation Discovery network, will air at 10 p.m. ET April 1 the story of Liberty German and Abigail Williams, two teen girls whose bodies were discovered Feb. 14, 2017, near the Monon High Bridge Trail in Delphi, one day after a relative dropped the girls off for a two-hour hike at the Delphi Historic Trails Park.

When the girls failed to show at an agreed-upon pick-up time, an all-out search commenced for the remainder of that day and night. The search ended around noon the following day when a volunteer searcher found their bodies about a half-mile off the trail.

“Now this case has captured national attention for years,” Walsh says in an advance screener of the episode Investigation Discovery provided Thursday to the Herald Journal. “Tonight, we’re asking you to give the tip that could break this case wide open.”

A little more than years and 50,000 tips later, police are still working to obtain what they said is the final tip that pulls the entire investigation into clear focus and identify the person they believe killed the girls. Despite a photograph, video and audio of the suspected perpetrator, determining the identity of that person remains elusive to investigators.

That’s where investigators hope Walsh and the ID network can get help.

The series stars Walsh and his son, Callahan, who hunt down persons of interest and help find missing children. They introduce the show’s viewers to unsolved violent crimes that “urgently need to be closed.”

The show relies upon viewers who may have seen something that would help authorities via calls and online tips, which are then vetted by experts and followed up on by the appropriate law enforcement agency, including local, state and federal authorities.

John Walsh is known for his anti-crime activism, with which he became involved following the murder of his son, Adam Walsh, in 1981. He later launched “America’s Most Wanted”— the longest-running crime reality TV show on the Fox and Lifetime networks and has helped capture more than 1,000 suspects between 1988-2012.

Callahan Walsh, the younger brother of Adam, conducted interviews with the victims’ families. Anna Williams, the mother of Abigail, mentioned to the Herald Journal last month that she spoke with Callahan in an interview for the show.

The show will also feature interviews with Indiana State Police Superintendent Doug Carter and ISP Sgt. John Perrine; Liberty’s grandparents, Becky and Mike Patty; and Liberty’s sister, Kelsi German, who reportedly was the last person to see them alive.

“It was a lot of mental and emotional stress. I am the person that dropped them off at the bridge that day,” Kelsi German says in the show. “And knowing that you’re the last person to talk to Abby and Libby, I constantly feel the frustration that I saw something that I don’t remember.”

The April 1 show will be the series’ second-season finale.