George Floyd, a 46-year-old bouncer, was killed on Monday May 25 by Derek Chauvin, a police officer, who pressed his knee into Mr Floyd's neck until he died while other police officers watched.

Footage of the killing, taken by a bystander, showed Floyd lying face down and handcuffed, groaning for help and repeatedly saying, "please, I can't breathe," before becoming motionless, reports The Telegraph.

Chauvin, had his knee on Floyd's neck for 8 minutes and 46 seconds in total and two minutes and 53 seconds after Mr Floyd was unresponsive, according to a criminal complaint released by the Hennepin County Attorney's Office.

On June 1, a medical examiner in Minnesota classified Mr Floyd's death as a homicide.

Mr Chauvin is charged with third-degree murder and second-degree manslaughter. Benjamin Crump, a lawyer for the Floyd family, has now called for the Minneapolis police officers to face the more serious charge of first-degree murder, based on the new findings.