Key witness in trial of former Dallas police officer Amber Guyger killed at his apartment

Officials say a witness who testified in the murder trial of former Dallas police officer Amber Guyger was shot to death Friday night. Joshua Brown’s testimony helped prosecutors piece together what happened when Guyger shot her neighbor, Botham Jean, ultimately leading to Guyger’s conviction. CBS News correspondent Omar Villafranca joined CBSN AM with the latest. Source