Derek Chauvin trial: Witness says he 'witnessed a murder'

Witness Donald Williams has testified for the second time during Derek Chauvin's trial. He said he called 911 during George Floyd's killing, "because I believed I witnessed a murder." Chauvin has denied charges of second and third-degree murder, and manslaughter, over the death of Floyd last May. He faces up to 40 years in prison if convicted of the most serious charges.