A use-of-force expert testified Wednesday that there was “absolutely no reason” for officer Jeronimo Yanez to believe Philando Castile was the armed suspect in a robbery days earlier, although a nonworking brake light was enough grounds for a legal traffic stop.

“It’s my opinion that the use of deadly force was objectively unreasonable,” said the prosecution’s witness, Jeffrey Noble. “He was simply a black man who drove by the convenience store four days later.”

Noble, a retired deputy police chief from Irvine, Calif., took the stand on the third day of testimony in Yanez’s manslaughter trial in Ramsey County. Thomas Kelly, one of Yanez’s three attorneys, said the defense will likely start its case Thursday morning.

“We expect to call several witnesses,” Kelly said.

Defense attorneys have indicated that Yanez could take the witness stand, telling jurors on different occasions that he “will” and “will likely” testify, although it’s unclear when that could occur.

Prosecutors have not yet rested their case.

Yanez, 29, a St. Anthony police officer, is charged with second-degree manslaughter for shooting Castile, 32, shortly after 9 p.m. last July 6, and two counts of dangerous discharge of a firearm for endangering Castile’s passengers, girlfriend Diamond Reynolds and her daughter, then 4.

Noble testified that Yanez had few details, including height or weight, when he linked Castile to an armed robbery suspect whom police had documented with a description and photo.

A transcript of Yanez’s car-to-car call that night was previously published in court, showing that Yanez called partner Joseph Kauser and said that Castile looked like the suspect because of his “wide-set nose.”

No other “reasonable” officer would have considered Castile the suspect, Noble said. (Authorities have said he wasn’t.)

“I mean, hundreds of black men had to have driven by,” Noble said. “That’s absurd.”

Prosecutor Jeffrey Paulsen replayed dashcam video of the traffic stop, during which Castile voluntarily told Yanez he had a gun, prompting the officer to order, “OK, don’t reach for it,” and, “Don’t pull it out.” Paulsen paused it several times to ask Noble what Yanez should have done differently.

Yanez should have instructed Castile to put his hands up or on the steering wheel or the dashboard, Noble said. “You want to see the hands.”

Paulsen stopped his questioning and stood still for five silent seconds, the amount of time that lapsed between Castile’s disclosure and Yanez’s discharge of seven shots.

“In those five seconds, did officer Yanez have other options than using deadly force?” Paulsen asked.

Yanez could have stepped back from in front of the driver’s window to the juncture of the driver’s and back passenger side door, also known as the “B pillar,” giving him time and space to react if a driver were to turn around with a weapon, Noble said.

Paulsen stopped the video again to show the arrival of four officers and asked Noble whether an officer who just came face-to-face with a gun and the possibility of death, which Yanez’s defense has maintained, would and should have warned his colleagues about the weapon.

“I would expect him to tell the other officers there’s a gun present and where he believes that gun to be at,” Noble said.

Prosecutors don’t believe Yanez ever saw the gun, which was later recovered from Castile’s front right shorts pocket.

Kelly tried to put a dent in Noble’s credibility during cross-examination, getting Noble to admit that his work analyzing police use of force is not a science, that he earned six figures annually for the past three years as an expert witness and that he was paid about $20,000 by the Ramsey County attorney’s office for his work on the Yanez case.

But Noble strongly resisted every attempt by Kelly to interpret Yanez’s words that night as signs that he saw a gun.

“What he said was, ‘I don’t know where the gun was,’ ” Noble said, quoting a conversation between Yanez and his supervisor that night.

“And you interpret that to mean officer Yanez never saw a gun?” Kelly asked.

“Well, yeah,” Noble said emphatically. “If you saw a gun, you’d know where it was.”

The nearly full courtroom burst into laughter, breaking a strict code of courtroom conduct set by Judge William H. Leary III.

Lindsey Garfield, a crime scene supervisor at the Minnesota Bureau of Criminal Apprehension, testified earlier in the day that Castile’s gun was loaded with a magazine but the chamber was empty.

Defense attorneys tried to counter that evidence to support the theory that Yanez perceived immediate bodily harm.

“There’s nothing to indicate whether there’s a round in the chamber or not?” Kelly asked. “That is correct,” Garfield said.

Kelly also continued the defense’s line of questioning about marijuana, asking Garfield what they found in the open ashtray in Castile’s car.

Cigarette butts and apparent loose-leaf tobacco, she said.

Kelly asked if people sometimes remove the paper from cigarettes to use for rolling marijuana blunts.

“I’m aware of that, yes,” Garfield said, adding that the BCA did not test the contents of the ashtray. Garfield testified that marijuana was found in a knotted plastic bag located inside a lidless Mason jar.

Toxicologist Dr. Kristin Engebretsen testified that post-mortem tests showed high levels of THC, the chemical compound found in marijuana, in Castile’s blood.

However, she said, post-mortem samples are not reliable because the compound is largely stored in fat, and death and injury causes it to redistribute in the blood.

Engebretsen testified as a prosecution witness, saying of marijuana’s effect, “Mostly it’s just a little euphoria.”

But defense attorney Earl Gray charged hard at bolstering Yanez’s case when he cross-examined Engebretsen.

He asked her if the drug could cause impaired coordination, difficulty thinking and an “inability to follow directions.”

Yes, Engebretsen answered.

Defense attorneys have argued that Castile was culpably negligent in his own death because he was high on marijuana and did not follow Yanez’s instructions.

Dr. Andrew Baker, chief medical examiner for Hennepin, Dakota and Scott counties, showed several graphic autopsy photos. Castile suffered 10 gunshot wounds, some of them likely from the same bullet: one grazing the tip of his right index finger, four in the upper left arm, one in the lower left arm, three in the left chest and one in the left hip area. Two rounds struck Castile’s heart and would have been fatal on their own, Baker said.

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