Liberty German and Abigail Williams wanted to enjoy a warmer-than-normal winter's day off from school when they were dropped off at the Delphi Historic Trails, near the Monon High Bridge, at around 1 p.m. on Feb. 13, 2017.

Libby, 14, took a photo of Abby, 13, walking on the bridge about an hour later and posted it on social media.

However, when a family member arrived around 3 p.m. to pick them up, the girls were nowhere to be found.

3 years later: Police insist case isn't cold

They were reported missing sometime after 4 p.m. Searches for the girls were initiated that evening and the next morning, until a grisly discovery was made: The bodies of both girls were found shortly after noontime on Feb. 14, in a wooded area about 50 feet from Deer Creek and a half mile east of the bridge.

Autopsies were conducted, but neither the coroner nor law-enforcement officials have told the media about how the girls died or when they were likely killed.

Here is what we do know about the case.

Details released to public

FBI description: The FBI said the suspected killer is a white man who weighs between 180 and 200 pounds. He stands between 5 feet, 6 inches tall and 5 feet, 8 inches tall, and was wearing blue jeans, a blue jacket or coat and a hoodie.

First image of suspect: The Indiana State Police released a grainy image of the man on Feb. 15, 2017, the day after the girls' bodies were found, but they would not initially reveal the source. A week later, on Feb. 22, they also released an audio recording of a man's voice saying "Down the hill." They confirmed then that both the image and recording were retrieved from Libby's smartphone, which was recovered at the scene.

First police sketch: In July 2017, police released a composite drawing based on the testimony of eyewitnesses who saw a man walking near the bridge on the Delphi Historic Trails at about the time the girls are believed to have disappeared. The man in the sketch appears to be in his 40s or 50s.

Second police sketch: On April 22, 2019, State Police released a new sketch of the suspect; in this sketch, the suspect looks to be much younger than the 2017 sketch. Police say the new sketch takes precedence over the old one and added that the killer is now thought to be between the ages of 18 and 40 — but may appear to be younger than his true age.

Longer version of video, audio: Police in April 2019 also released a longer version of the audio and video that had been recovered from Liberty's phone. This version of video shows the gait of the man as he was walking on the bridge, the same man shown in the grainy image released the day after the girls' bodies were found.

Proximity of suspect: At the same April 2019 press conference, Doug Carter, superintendent of the Indiana State Police, said new information leads investigators to believe that the killer is from Delphi, and they believe he either still lives or works in Delphi, or frequently visits the area.

"We have a strong suspicion that the person is either from the area, has visited there before or has lived in the Delphi area for a number of years," said Sgt. Kim Riley of the State Police, who has served as a spokesman in the investigation.

Could there be multiple suspects? Investigators have never said for certain whether there was only one suspect in the slayings. When asked whether they could be looking for more than one person, Riley said: "We're not ruling out anything at this point in time." It's for that reason that investigators don't want to completely discount the earlier police sketch of what looks to be an older suspect. "There still the possibility of a second person involved in this case," Riley said. "We don't want to say the old sketch is not involved, we just want to say that this new sketch is more indicative of what we're looking for at this time."

DNA evidence: Police have not confirmed whether DNA evidence was collected at the crime scene. However, if DNA was found, a new state law in 2018 could help in the case: Now DNA evidence can be collected from anyone accused of a felony — not just from someone already convicted of a crime, as had been the practice in the past.

How to offer a tip, claim reward

Anyone with information about the killings or the person in the sketch should call the Delphi homicide tip line at 844-459-5786. Tips also may be emailed to abbyandlibbytip@cacoshrf.com.

Prosecutors are looking for specific information in such tips, including the name of the suspect or person of interest; a detailed description and personal identifiers, such as tattoos or birthmarks; age or birthdate; last known address or place where the person is often seen; and lastly, their possible motivation and connection to the case.

Regarding a reward: The Indiana State Police Alliance is collecting money for the Delphi Reward Fund for information leading to an arrest in the slayings. The reward could be as much as $216,165, according to their website.

Journal and Courier reporter Ron Wilkins contributed to this article.

Call IndyStar digital producer Dwight Adams at 317-444-6532. Follow him on Twitter: @hdwightadams.