DELPHI, Ind. (WISH) – The reward for information leading to an arrest in the murders of 13-year-old Libby German and 14-year-old Abby Williams has increased.

The reward has increased by $9,000 after the office of United States Representative Todd Rokita donated the money, bringing the total up to $50,000.

The FBI donated $25,000, the Indiana Packers Corporation donated $10,000 and the Lafayette Bank and Trust donated $1,000 on top of the $9,000 donation from Rokita’s office.MORE: Police release audio of suspect in Indiana girls’ deaths

“From all the investigators in this case and from the family of Libby and Abigail, thank you,” Indiana State Police Sgt. Tony Slocum said.

The bodies of German and Williams were found on Feb. 14 around 12:15 p.m. in a wooded area near the Delphi Historic Trail in Carroll County. The teens’ bodies were found during an organized search for the girls.

Officials have received approximately 3,900 tips by the phone and email. Roughly 1,900 of those tips were received after authorities released a voice recording that came from German’s cell phone.

MORE: FBI using billboards for tips in killings of 2 Indiana teens

The FBI has launched a digital billboard campaign for the case in 46 states, with approximately 6,000 electronic billboards requesting information.

If you are interested in donating money toward the reward, individuals or businesses should make checks payable to the Indiana State Police Alliance Foundation. You must enter “Delphi Reward” on the memo line. You are asked to mail donations to 1415 Shelby Street, Indianapolis, IN, 46203.

“Some people are motivated by doing the right thing. Some are motivated by a monetary sum,” Slocum said. ” Most likely the higher the reward, the more likely someone may be to give up a person that maybe wouldn’t otherwise.”

If you would like to leave a tip, you are asked to call the Delphi Murder Tip Line at 1-844-459-5786, or you can email your tip to:

Click here to hear the suspect saying “down the hill.” The audio and photo released of a suspect were taken from the cell phone of one of the victims, Libby German.