A Minneapolis police lieutenant has testified that the former officer accused of murdering George Floyd had been taught to avoid kneeling directly on a handcuffed suspect’s neck.

Lieutenant Johnny Mercil, who directly trained Derek Chauvin in the use of force, said Minneapolis police are taught to restrain combative suspects with a knee on their back or shoulders if necessary.

Chauvin, 45, is charged with murder and manslaughter. He is accused of killing Mr loyd, 46, who was arrested in May 2020 after police were called to reports he had used a counterfeit $20 note.

Bystander video of Mr Floyd crying that he couldn’t breathe as onlookers yelled at Chauvin to get off him sparked protests around the US and the world.

Lieutenant Mercil is the latest person to give evidence against Chauvin.

He told the jury at Chauvin’s trial that officers are told to “stay away from the neck when possible”.

Asked if Chauvin’s decision to kneel on Mr Floyd’s neck was allowed under department policy, Lieutenant Mercil said “no”.

He acknowledged that officers are trained to use neck holds, but said they are generally taught to do so with their arms.

George Floyd’s former partner, Roxie Washington, and his daughter, Gianna, at his funeral. Photo: Getty

The trainer then went on to demonstrate the hold to the court.

Records show Chauvin underwent training in the use of force in 2018.

Lieutenant Mercil said those who attended were taught that the sanctity of life is a cornerstone of the department’s use-of-force policy and that officers must use the least amount of force required to get a suspect to comply.

According to testimony and records submitted on Wednesday morning (Australian time), Chauvin also took a 40-hour course in 2016 on how to recognise people in crisis, including those suffering mental problems or the effects of drug use, and how to use de-escalation techniques to calm them down.

Sergeant Ker Yang, the Minneapolis police official in charge of crisis-intervention training, said officers are taught to “slow things down and re-evaluate and reassess”.

Mr Floyd appeared cheerful in surveillance footage taken before his arrest. 

Lieutenant Mercil testified that in his experience, it takes less than 10 seconds for someone to be rendered unconscious with a neck restraint.

He said someone having a rush of adrenaline or a higher breathing or heart rate can be affected even faster.

Chauvin’s attorney Eric Nelson has argued that the now-fired white officer “did exactly what he had been trained to do over his 19-year career,”.

The defence has suggested that Mr Floyd’s use of illegal drugs and his underlying health conditions are what killed him, not Chauvin’s knee.

Mr Nelson has also sought to point out moments in the video footage when Chauvin’s knee did not appear to be on Mr Floyd’s neck.

He showed Lieutenant Mercil several images taken from officers’ body-camera videos, asking after each one whether it showed Chauvin’s knee appearing to rest more on Mr Floyd’s back, shoulder or shoulder blades than directly on Mr Floyd’s neck.

Lieutenant Mercil often agreed.

Mr Nelson acknowledged the images were difficult to make out.

They were taken at different moments during Mr Floyd’s arrest, starting about four minutes after he was first pinned to the ground, according to time stamps on the images.

The trial continues.

-with AAP