CNN  — 

In the two years since Libby German and Abby Williams were killed on a hiking trail, tipsters have given police 38,000 leads to help find the Indiana girls’ killer.

But the assailant is still nowhere to be found. Now police are releasing a new sketch and additional video from a victim’s cell phone in hopes the case will finally be solved.

Indiana authorities are asking for information about the man depicted in this sketch.

Libby, 14, and Abby, 13, were reported missing on February 13, 2017, after they went hiking at Delphi Historic Trails in Indiana.

Libby German (left) and Abby Williams

When they didn’t show up at a designated meet-up time, an extensive search ensued. Their bodies were found the next day in a wooded area near the trails, about a half mile upstream from where they had been dropped off.

On Monday, Indiana State Police Superintendent Doug Carter said he believes the suspect lives in, works in or frequents the Delphi area.

“We believe you are hiding in plain sight,” Carter said at a news conference. “For more than two years, you never thought we would shift gears to another investigative strategy. But we have.”

The police chief continued speaking openly to the killer, who he said “may be in this room.”

“What will those closest to you think of when they find out you brutally murdered two little girls – two children? Only a coward would do such a thing,” he said.

“We are confident that you have told someone what you have done. Or, at the very least, they know because of how different you are since the murders.”

The killings devastated the Delphi community, which rallied to try to find the killer. Investigators have received a dozen or more new tips every day, Carroll County Prosecutor Nicholas McLeland said in February.

Authorities originally released a grainy photo of a suspect, which shows a man wearing blue jeans, a blue coat and a hoodie.

Indiana State Police released this photo of a man who was on the Delphi Historic Trails on February 13, 2017, around the time the teens went missing.

At that time, officials also released audio of a male voice saying the words “down the hill,” hoping someone might identify the suspect’s voice. The voice recording was taken from a video found on Libby’s cell phone, police said.

Indiana State Police spokesman Capt. Dave Bursten has praised Libby as a hero for having the presence of mind to turn on her video camera.

But the tragedy has been grueling for the girls’ families.

Kelsi German, Libby’s sister, remembered Libby as a fun, outgoing person who loved playing sports and was interested in photography. She said she last saw Libby and Abby when she dropped them off on the hiking trails two years ago.

“They got out of my car. I made sure they both had sweatshirts and told them goodbye. I told Libby I loved her,” German told HLN in February. “They walked out, and that was the last time I saw them.”

CNN’s Eric Levenson, Carma Hassan and Amanda Watts contributed to this report.