The top use-of-force trainer for the Minneapolis Police Department said Tuesday that Derek Chauvin’s knee restraint on George Floyd is not authorized — and never has been.

Lt. Johnny Mercil testified at Chauvin’s murder trial in Floyd’s death that, while the department allows neck restraints in certain situations, the ex-cop’s decision to keep his neck on the victim’s neck for more than 9 minutes is not allowed.

“Sir, is this an MPD-trained neck restraint?” prosecutor Steve Schleicher asked.

“No sir,” Mercil, who trains MPD cops in Brazilian jiu-jitsu and other martial arts, replied.

“Has it ever been?” Schleicher said.

“Not to my — neck restraint? No, sir,” Mercil answered.

He said a neck restraint could render someone unconscious in “under 10 seconds.” 

Asked under what circumstances a neck restraint could be used by a cop based on the training, Mercil said it would depend on the amount of resistance from a suspect.

“So, if there was, say, for example, the subject was under control and handcuffed, would this be authorized?” Schleicher asked him.

“I would say no,” the cop replied.

Chauvin, 45, is on trial on second-degree murder, third-degree murder, and second-degree manslaughter in Floyd’s May 25 death.

Chauvin’s lawyer, Eric Nelson, has maintained that Floyd died as a result of drug use and a heart ailment — not the former cop’s conduct.

In cross-examination by Nelson Tuesday, Mercil conceded that “passive” and “compliant” suspects can suddenly turn unruly and aggressive.

But the use-of-force expert, who testified that he has trained “hundreds” of officers in the use of neck restraints, also told the defense attorney that the one restraint allowed by the department is a knee across the shoulder blade — rather than the neck.

Nelson then displayed photos of Chauvin’s hold on Floyd that indicate the ex-cop’s knee was pressed into the shoulder blade — although other images do appear to show Chauvin’s knee on Floyd’s neck.

In addition, viral video of the incident shows the former cop pressing his knee to the back of Floyd’s neck for more than nine minutes — despite pleas from bystanders to let him get up.

In testimony Monday, Minneapolis Police Chief Medaria Arradondo also said that Chauvin should have lifted his knee after Floyd became unresponsive.

“Clearly, when Mr. Floyd was no longer responsive, and even motionless, to continue to apply that level of force to a person, prone, handcuffed behind their back, that in no way, shape or form is anything that is by policy, is not part of our training, and it is certainly not part of our ethics,” the chief said.

Two other ranking officers — Lt. Richard Zimmerman, the department’s top homicide detective, and Sgt. David Pleoger — both concurred during testimony last week.

But Nelson has also suggested that a crowd of angry bystanders hampered police efforts to de-escalate the situation during Floyd’s arrest.