By Bill Kirkos and Holly Yan

CNN

ST. PAUL, Minnesota (CNN) -- Philando Castile was calm and polite when an officer pulled him over for a broken taillight, a prosecutor said Monday, yet he still died in a barrage of gunfire.

Castile "did what he was supposed to do. He was courteous. He was nonthreatening. He had no complaints," prosecutor Jeffrey Paulsen said at officer Jeronimo Yanez's manslaughter trial.

Then, "without any warning ... (Yanez) fired seven rounds into that car. He killed PhIlando Castile and endangered the lives of Diamond Reynolds and her daughter."

Reynolds, Castile's girlfriend, didn't just watch her boyfriend die slowly right next to her. She made sure the world watched, too, by broadcasting Castile's final moments on Facebook Live.

In that Facebook video, Castile -- bleeding heavily -- insists that he hadn't been reaching for his gun, which he had a permit to carry. Reynolds said Castile was reaching for his ID in his back pocket when he was shot.

But during closing arguments on Monday, Yanez's defense team said Castile reached for his gun when he was told not to. An audio recording captured Castile telling the officer he had a gun in the car, and the officer telling Castile not to reach for it.

Castile also resembled a suspect from a robbery days earlier, defense attorney Earl Gray said.

"We have this fellow who looks like the robbery (suspect), he (the officer) smells marijuana, and he says, 'Don't reach for it' -- and he (Castile) is ignoring him," Gray said Monday.

He said it was reasonable to deduce that Castile had smoked marijuana the day of the shooting because THC, the main psychoactive chemical in cannabis, was found in his blood.

Gray told the jury that Castile would still be alive if he "wasn't stoned" and had followed instructions.

Now, a jury must decide whether Yanez should be convicted of three charges against him: one count of second-degree manslaughter for the death of Castile, and two counts of "intentional discharge of firearm that endangers safety" for shooting into a car with Reynolds and her daughter inside.

Officer: 'I thought I was going to die'

During his testimony Friday, Yanez said he saw Castile's hand on a gun.

"I had no other choice. I didn't want to shoot Mr. Castile. That wasn't my intention," Yanez said while wiping tears from his eyes, CNN affiliate WCCO reported. "I thought I was going to die."

After the shooting, the Facebook Live video showed Yanez keeping his gun aimed at Castile while he waited for backup.

Prosecutor Rick Dusterhoft recounted those moments while trying to discredit the officer's claim that he saw Castile reach for a gun.

"When Roseville police officers arrived, you never warned them there was a gun, did you?" Dusterhoft asked.

"No," Yanez said.

Yanez is still a member of the St. Anthony Police Department, though he has been on paid administrative leave since the July 2016 shooting. His police union is paying for his attorney fees.

If convicted of manslaughter, Yanez could be sentenced to up to 10 years in prison. He could also face up to five years in prison if convicted on either of the endangerment charges.

Bill Kirkos reported from St. Paul, and Holly Yan reported and wrote from Atlanta.