Expert says Floyd died from a lack of oxygen

In this image from video, prosecutor Jerry Blackwell questions Dr. Martin Tobin as Hennepin County Judge Peter Cahill presides Thursday, April 8, 2021, in the trial of former Minneapolis police Officer Derek Chauvin at the Hennepin County Courthouse in Minneapolis, Minn. Chauvin is charged in the May 25, 2020 death of George Floyd.