CHICAGO (CBS)—The investigation into the murders of two Indiana teenagers is moving in a “new direction,” authorities say.

Indiana State Police plan to announce new developments in the case on Monday.

Composite sketch and cell phone image of the prime suspect in the murders of two teenage girls in Delphi, Indiana, in Feburary 2017. (Credit: Indiana State Police)

Libby German, 14, and Abby Williams, 13, were killed near Delphi, Indiana in February 2017.

The girls disappeared while on a hike, and their bodies were found a day later in a wooded area.

One of the only clues in the case is a cellphone video of the man believed to be behind their murders.

He has never been identified, police say.