The CrimeDoor app is hoping they can help law enforcement bring the unsolved Delphi case to a close with new technology. CrimeDoor created a 3-D application they say allows users to "step inside" the crime scene through augmented reality. This opportunity gives the public a first-hand look at the area where teens Libby German and Abby Williams were last seen alive.

On February 14, 2017, police say the corpses of both teens were found dead near an Indiana bridge. Since then, the hunt has been on for their killer or killers.

Libby's sister Kelsi German, who is teaming up with CrimeDoor, told WTHR, "It really brought into perspective what they were seeing and the person being there gave me a perspective of what he looked like." German adds, "It's going to help trigger somebody's memory and they are going to say, 'Wow. I really know who this looks like."

According to a press release, users can have their own experience and investigative the case themselves. The husband and wife team, Neil and Lauren Mandt, who developed CrimeDoor, are hoping their new venture can bring resolution to Abby and Libby's families.

"CrimeDoor does not celebrate killers but gives a voice to the victims. Our attention to detail in recreating the crime scenes is our highest concern. Helping to solve a crime would be the most important moment in my life, and I feel confident this technology will be pivotal in doing just that," Neil Mandt adds.

One reason this particular homicide case came to national attention and was covered by In Pursuit with John Walsh is the haunting cell phone and social-media clues the girls left behind. On February 13, 2017, just after 2 p.m., Libby posted a photo to Snapchat of Abby walking on the bridge. In the distance, if you look close, you can see a man approaching.

A closer photo of a man walking, perhaps the same man, was also found on Libby's phone and released, in hopes of a lead in the case. A composite of photos of this man and of other photos of the bridge area have been turned into a composite video and hosted on AbbyAndLibby.org, giving the impression of the suspect walking on the bridge.

But it wasn't just photographic evidence the girls left behind. Investigators also discovered an audio recording on Libby's phone, of a man with a deep voice, and they've released a section of it in which he is saying, "Down the hill."

In 2017, investigators released a sketch of a man they believed could have possibly been involved, but in 2019, the sketch was updated. Now authorities say the suspect could be between the ages of 18 - 40 and it's possible he's "hiding in plain sight."

Callahan Walsh, Co-Host of In Pursuit with John Walsh, visited the crime scene at the Monon High Bridge Trail and has worked closely with law enforcement on the case.

Walsh previously told Inside Edition about the bridge and the area, “That is something that an individual would need to have experienced crossing to get over. And that person who followed Abby and Libby across the bridge made it across with no problem. It makes me believe that that person knew that area well, that (they) knew that terrain, because it's very difficult terrain, and had experience in that area.”

As for German, she's not giving up, "I still have so much hope. I talked to an investigator the other day. He told me to remember that they are never stopping."

If you know anything about this case, please reach out to the "In Pursuit with John Walsh" hotline directly with your tips.

You call Monday through Friday to speak with someone between the hours of 9 a.m. - 5p.m. EST or text the same number 24/7. Remember you can always remain anonymous: 833-378-7783 (PURSUIT)

Read more: CrimeFeed

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