Welcome to the lead. I am Jake Tapper and we start today with our national lead, the trial of former Minneapolis police officer Derek Chauvin,

which today intently focused on the use of force by officer Chauvin. This afternoon we heard from the special agent who investigated Chauvin's actions.

And as the person who handled much of the evidence in the case, special agent James Ryerson confirmed exactly how long officers stayed on top of George Floyd.

And how long Chauvin had his knee on Floyd's neck even after Mr. Floyd had stopped speaking and became unresponsive.

Today we also heard from a Los Angeles police sergeant hired by the prosecution as an expert when it came to use of force.

He testified that the amount of force Derek Chauvin used against Floyd was in his opinion, his opinion, excessive.

But he also said that some of Chauvin's actions were, in his view, reasonable as CNN's Omar Jimenez reports.

Today's testimony more cops taking the stand against former officer Derek Chauvin.

In your opinion does defendants use of force during that time period need to be reasonable within the entire time period.

Yes, Sergeant Jody Steiger from the Los Angeles Police Department was called by prosecutors as a use of force expert.

And testified, like others have, the force Derek Chauvin used on George Floyd was excessive.

He was in the prone position, he was handcuffed, he was not attempting to resist, he was not attempting to assault the officers, kick, punch or anything of that nature.

But Chauvin's attorney during cross-examination focused on what could have happened, specifically one of their central arguments that the growing crowd became a perceived threat and distracted Chauvin.

And when someone starts threatening you, it's a possible possibility that an officer can view that as a potential deadly assault is about to happen.

That's what they're trained.

Yes, that's what they're trained.

But during prosecutor questioning, I did not perceive them as being a threat.

And why is that? Because they were merely filming and most of it was their concern for Mr. Floyd.

The defense also moved to show there were points where Chauvin's knee may not have been on the neck but on some portions of the shoulder.

Prosecutors called the placement irrelevant.

Is the risk related to the pressure on the neck or the pressure on the body?

The pressure on the body, any additional pressure on the body complicates breathing more so than if there was no pressure at all.

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