The voice of the suspect in the killing of Liberty German and Abigail Williams was possibly captured on audio

The widely circulated photo of the main suspect in last week’s double homicide of two Indiana teens was taken by one of the victims before she was killed, police announced Wednesday.

On Feb. 14, the bodies of Liberty German, 14, and 13-year-old Abigail Williams were found by authorities less than a mile from where they were last seen alive. The evening before, they had been reported missing after having been dropped off to go hiking earlier that day.

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At a press conference on Wednesday morning, police announced Liberty had not only taken the photo of the male suspect but also recorded a video moments before her death that includes audio of a man talking — though officials are not sure the voice belongs to the suspect.

“This young lady’s a hero, there’s no doubt about it,” Indiana State Police Public Information Officer Sgt. Tony Slocum said of Liberty’s quick thinking. “To activate the video system on her cell phone to record criminal behavior that’s about to occur … there’s no doubt in our minds that [this] young lady is a hero.”

Image zoom The suspect in the double homicide Indiana State Police

In the six-second clip, a man’s voice can be heard saying “down the hill.” (The clip can be heard here.)

“It’s important that we spread that person’s voice far and wide for somebody [to] recognize who it is and call us and tell us,” Captain David Bursten of the Indiana State Police said Wednesday.

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While police initially did not suspect foul play in the girls’ disappearance, they later announced they were victims of a double homicide.

During the hike, Liberty posted a photo to Snapchat of Abigail walking alone on an abandoned bridge known as Monon High Bridge. The friends were supposed to be picked up from the trails by family later that afternoon, but they never showed up to the pickup location.

Image zoom Liberty German Facebook

Police do not know whether the girls’ killer used social media to see where they were. Authorities have not discussed a motive.

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The girls’ bodies were found nearly 60 feet from the edge of a creek on private property, police said last week. Officials would not comment on the girls’ cause of death or whether they had any obvious injuries.

“She went hiking often,” Mike Patty, Liberty’s grandfather, previously told PEOPLE of his granddaughter, who he raised alongside his wife, Becky.

“We talked all the time [about safety], it was something that I stressed, but I guess not enough,” Patty said.

Image zoom Liberty German and Abigail Williams Facebook

Police to Suspect: ‘We’ll Find You’

At Wednesday’s press conference, officials addressed the suspect directly.

“If you’re watching, we’ll find you,” Superintendent Douglas Carter of the Indiana State Police warned. “Who’s next? I hate to ask you that question. I’d give my life to not have to, but I know you’ve asked that yourself that very question.”

Carter added: “Someone knows who this individual is— is it a family member? Is it a neighbor? Is it an acquaintance? Is it an associate? Or maybe [it’s] that one guy who lives over at that one place that’s kind of not right.”

Image zoom Facebook(2)

Federal investigators do not believe the suspect is a serial killer, Assistant Special Agent in Charge Greg Massa of the FBI said Wednesday.

Police urge anyone with possible tips to contact authorities. Reward for any tips leading to the arrest of Liberty and Abigail’s killer is $41,000, officials said. Tips can be made anonymously by email or telephone.

Anyone with information should email ABBYANDLIBBYTIP@CACOSHRF.COM or call 844-459-5786.