Police investigate new development in murder of 2 girls in Delphi, Ind.

DELPHI, Ind. -- Police in Delphi, Indiana are looking into a possible new development in the cold-case murder of two teenage girls.

Abby Williams, 13, and 14 year old Libby German were killed on a hiking trail in February 2017. Libby recorded their attacker's voice and snapped a photo of a man police call a person of interest, but their killer still hasn't been found.

Now, investigators said they're looking into whether a man arrested in a sting this month more than 100 miles away on suspicion of child molestation could be connected. The sheriff's department there said Charles Andrew Eldridge admitted to multiple sex acts with a minor.

The public called in tips, flagging what they said is a strong similarity between his mugshot and this sketch of the killer, ABC News reports.

"The reality is law enforcement, even if they think he's the right guy, what evidence do they have to prove he is the right guy?" said former FBI Agent Brad Garrett.

Indiana State Police said, "Many similar tips and arrests of other persons alleged to be connected to the Delphi murders occur with some frequency" and all are investigated.

There is still a reward of more than $200,000 for information leading to the arrest and conviction of the killer.