Authorities are now saying they are looking into a possible connection between a kidnapping suspect and the 2017 killings that rocked the small community.
A potential new lead was announced Thursday in the unsolved murders of 13-year-old Abby Williams and 14-year-old Libby German -- those two eighth-grade girls -- last seen Snapchatting on a hiking trail in Delphi in 2017.
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But despite a photo and audio of the suspect, captured by German's cell phone, their killer has never been found.
Now, more than four years later, investigators say they are "looking into" a person they believe "might" be connected to their murders.
Last week, police arrested 42-year-old James Chadwell, charging him with the kidnapping and attempted murder of a 10-year-old girl, in Lafayette, Indiana, about 20 miles from Delphi.
The local sheriff told ABC News there are "several factors" leading them to look into Chadwell, but he declined to go into detail.
Chadwell has pleaded not guilty to the charges against him, and has not responded to requests for comment regarding a possible connection.
The girls' murders have haunted the town of Delphi for years.
"I think about them all the time; their names are etched in my desk," Indiana State Police Superintendent Doug Carter said.
Back in 2017, authorities released a grainy photo of a suspect they said was on the trail the same day the eighth graders went missing.
With no arrests, they later released video footage recovered from German's cell phone, along with audio believed to be the suspect's voice.
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Police said they believed German recorded it because she feared they were in danger.
"Watch the mannerisms as he walks. Do you recognize the mannerisms as being someone that you might know..." Carter asked.
Believing the killer was likely a local, investigators initially released a sketch of the suspect, but in 2019 they released a new younger-looking suspect sketch based on a witness' recollection, potentially placing the man between 18- and 40-years-old.
"To the killer who may be in this room: We believe you are hiding in plain sight," Carter said.