Prosecutor Jim Griffin told jurors that Burnley Jr. boarded an MCTS bus on Brown Deer Road and became argumentative after the driver told him about a change in policy related to bus transfers.
The bus driver told investigators she continued along her route until she spotted a pair of Brown Deer Police squad cars parked near 60th and Brown Deer Road. The bus driver pulled over and flagged down the two officers.
Kraemer and Officer Michael Leeman boarded the bus and talked with Burnley Jr.
According to investigators, Burnley Jr. remained argumentative and refused to comply with instructions from police as he was escorted off the bus.
Jurors on Wednesday viewed a grainy video that showed Burnley Jr. being led off the bus and resisting as the two officers tried to handcuff him. A struggle ensued in which Burnley Jr. and the two police officers all fell to the ground.
Kraemer's attorney said she feared for her safety, as well as the safety of her partner, and could not see Burnley Jr.'s left hand during the struggle.
At the time of the altercation, Kraemer, who is 5'-5" tall, weighed roughly 140 pounds. The 5'-10" Burnley Jr. weighed roughly 370 pounds.
"He's moving his arms, he's thrashing around, and he doesn't want to be handcuffed," said defense attorney Chris MacGillis.
"(Kraemer) was scared that if she doesn't stop the threat, either she or the Officer Leeman could be seriously hurt or killed," he said.
At some point, Kraemer fired a single round into Burnley Jr.'s back. He was injured and lost part of a lung.
Griffin told jurors in the prosecution's opening statement that evidence presented during the trial won't back up Kraemer's claim of an imminent threat.
"His left hand was not pinned underneath his body on the ground. It was out there where she could see it," Griffin said.
"Yes, (Burnley Jr.) is foul-mouthed. But not one time did he punch an officer. Not one time did he kick an officer," Griffin also said.
Kraemer's attorney said that, at one point, Burnley Jr. put his hand on Leeman's throat.
Following opening statements, Griffin called use of force training export Emanuel Kapelsohn to the stand as the state's first witness.
Kapelsohn testified that surveillance video from the bus backs up claims from Kraemer and the bus driver that Burnley Jr. was being argumentative.
But Kapelsohn said, in his opinion, Kraemer and Leeman didn't treat Burnley Jr. like a suspect they believed was armed.
He said they allowed him to reach into a pocket, with a phone in his hand, while they spoke to him on the bus.
Kapelsohn also said Kraemer's decision to holster her weapon after firing a single round into Burnley Jr.'s back doesn't indicate she believed he was capable of producing a weapon of his own.
"It makes no sense to shoot him once, have him still moving around, and then put your gun away, if this is a deadly threat," Kapelsohn said.
He said officers are trained to keep their firearms drawn and/or keep firing until a suspect is no longer an imminent threat.
Burnley Jr. was never charged in connection with the incident.
Kraemer is currently on administrative suspension from the Brown Deer Police Department, according to Chief Michael Kass.