Authorities in Rapid City need your help finding out what happened to a missing woman.

21-year-old Larissa Lonehill disappeared in October.  

Police don’t believe she’s alive, and they’re trying to track down anyone who may have been involved in the young mother’s disappearance.

They are offering a $5,000 reward.  

Anyone with information is asked to contact Detective Ryan Gebhard at 605-394-4134.