The suspect has been described as 5-foot-6 to 5-foot-10, weighing between 180-220 pounds with reddish brown hair.
Investigators are asking the public to study the man's facial features and contact them with any information on him.
State police believe this new sketch may help identify a man who appeared in two previously released photos that were taken on the Monon High Bridge in Delphi, Indiana on February 13 when Abby and Libby disappeared.
Fourteen-year-old Liberty German vanished with 13-year-old Abigail Williams on February 13 while hiking a trail near their hometown of Delphi, about 60 miles (100 kilometers) northwest of Indianapolis.
Investigators hope that this, alongside the sketch, will allow for more aid from the community.
Authorities have received thousands of tips in the case and questioned hundreds of people, but so far no arrests have been made in the brutal murders of the two teens.
Earlier, police released a grainy image of a suspect and an audio recording of man saying, "Down the hill".
Abigail "Abby" Williams, left, and Liberty "Libby" German.
The reward for information that leads to an arrest and conviction is upwards of $230,000. Their bodies were found about 12:15 p.m. a day later. Anyone with information about the murders or person in the composite sketch is asked to call the anonymous tip line at 844-459-5786.
Investigators released this photo of a man seen on the Delphi Historic Trails in Delphi, Indiana on Monday, Feb. 13, 2017, the same day two girls were killed.