COON RAPIDS, Minn. (FOX 9) – Authorities in the northern metro are investigating a homicide on Friday that left three people dead in Coon Rapids. According to the Anoka County Sheriff’s Office, dispatch received a 911 call around 12:24 p.m. with an open line and “sounds of disturbance” in the background. An “open line call” is when a call has been placed, but no one is actively responding.