DELPHI, Ind. (AP): A northern Indiana sheriff says investigators remain confident they’ll solve the case of two teenage girls slain two weeks ago.

Carroll County Sheriff Tobe Leazenby says authorities continue their work reviewing more than 7,000 tips they’ve received in the killings of 14-year-old Liberty German and 13-year-old Abigail Williams.

The Delphi girls’ bodies were found Feb. 14 in a wooded area near the small city about 60 miles northwest of Indianapolis. They had vanished the day before while hiking.

Leazenby says investigators remain “very confident and optimistic” they’ll eventually make an arrest, but continue to seek the public’s tips in the case.

Authorities have released a grainy photo of a man and audio of a male saying “down the hill.” That evidence came from German’s cellphone.

The police tip line for the case is 844-459-5786. Tips can also be reported by emailing Abbyandlibbytipcacoshrf.com.