Authorities in Indiana on Wednesday released a haunting, three-word audio clip extracted from video found on the phone of a 14-year-old girl who was found murdered with her friend last week.

The video was taken by Liberty Rose Lynn German, 14, who was found on Feb. 14 along with Abigail Joyce Williams, 13, in a wooded area near the Delphi Historic Trail, roughly one-half mile upstream from the Monon High Bridge, where they were dropped off a day before to hang out, Indiana State Police Sgt. David Bursten told reporters.

Bursten said a man can be heard saying “down the hill” on the recording, which was played several times for reporters during an update on the double murder investigation that has gripped Delphi, a town of roughly 3,000 people about 75 miles northwest of Indianapolis.

“Liberty had the presence of mind to turn on the video camera,” Bursten said, adding that looped audio of the recording is available on the Indiana State Police website. Investigators now hope someone from the community will recognize the voice, although it’s unclear whether the man heard in the recording is the same one depicted in an image of a suspect released by authorities last week.

“There’s enough there that somebody could recognize this person’s voice,” Bursten said, who at times spoke directly to the public. “You may tell us who the right person was.”

Authorities have additional video evidence but aren’t releasing it to preserve the integrity of the investigation. Bursten said investigators are still trying to determine whether the killings were the result of a chance encounter on the remote trails or if whoever committed the murders knew that the girls would be there on Feb. 13.

“There’s nothing off the table,” he told reporters.

Bursten said it’s possible that even more than one person could be behind the killings, but investigators believe the suspect whose image was released last week at least participated in the double murder. The man in the photograph appears to be wearing blue jeans with a blue coat and a hoodie.

Greg Massa, assistant special agent in charge of the FBI’s Indianapolis field office, asked residents of Delphi and nearby communities to go back to Feb. 13 in hopes of identifying anyone who did anything unusual that day, including someone who canceled an appointment, called out sick from work or backed out of a social engagement — even with a plausible excuse.

“That may be important,” Massa said. “Did their behavior change? Is their sleep pattern different now? Have they been anxious, nervous, irritable? Have they been following this case with a sense that’s not normal?”

Other possible changes in behavior or appearance — like unexpected travel or a drastic haircut — should also be considered, said Massa, adding that there’s no indication that the murders are the work of a serial killer or are connected to other homicides.

Indiana State Police Superintendent Douglas Carter said FBI Director James Comey has been briefed on the case, which has seemingly taken an emotional toll on him.

“Words tend to escape during these periods of times,” Carter said. “Why Libby? Why Abby? Why Delphi? Why Carroll County? Why the region, why the state, why even the nation? I say that because this is a classic example that evil lives amongst us.”

Prior to their disappearance, Liberty posted a photo on Snapchat of Abigail looking somber on a railroad bridge in Delphi. The post marked the last time either girl was seen alive, Time reported.

Anyone with information about the case is asked to call the Delphi Homicide Investigation Tip Line at (844) 459-5786.