As the expert began to explain the final wound, Yazzie's family left the 3rd District courtroom, tears streaming down cheeks, hands shaking as they reached for the door.
Adam Karr, 27, is the final defendant in Yazzie's death. He has been charged with first-degree felony murder and second-degree felony obstruction of justice and faces up to life in prison if convicted of murder.
His trial, which began this week, may be the last time Yazzie's relatives have to relive the details of the 22-year-old's demise.
It may also be their last shot at justice.
For nearly a year, they have waited for someone to stand trial for the killing. In November, they watched Karr's younger brother, Ammon Karr, and his teenage cousin strike deals that would keep them out of prison.
But this time, they want a jury to hold someone responsible for Yazzie's death.
More than a dozen of Yazzie's relatives have attended this week's proceedings. They've held hands and passed out tissues as witnesses recounted Yazzie's final moments.
Several of those who attended a party at the Karrs' home, near Girard Avenue (560 North) and Desoto Street (40 East), on the night Yazzie was killed testified on Thursday.
They talked about a good time gone too far. There were drinks and drugs. Tensions rose by the minute.
Yazzie, who several people said had been drinking before he arrived at the party, was being "obnoxious," partygoers testified.
He was sloppy, slurring, stumbling. He knocked things over and hit some of the boys' baseball caps off of their heads. He was told to "chill out or get out" several times, witnesses said.
Marisa Lee, 18, testified that Yazzie sat on her lap and wouldn't leave her alone. She punched him in the shoulder to make a point, she said. Soon after, the hosts decided it was time for Yazzie to leave.
Ammon Karr pushed Yazzie upstairs from the basement and out the door. The two, who had been bickering all night, began to quarrel, witnesses said.
Things escalated quickly. A punch was thrown, then another.
Before long, Ammon Karr had put Yazzie in a choke hold, said Pepeen Rios, 19.
That's when Adam Karr ran outside toward the pair. At first, Rios said, it looked as if Adam Karr was punching Yazzie, who was still restrained, in the stomach fast uppercuts with a closed fist.
But when the older brother backed away from Yazzie, who stumbled down the steps in front of the house and collapsed in the front yard, Rios said he knew it had been a stabbing, not punching.
"There was blood," Rios said. "Lots of blood on [Yazzie's] shirt."
Lee said she also suspected Adam Karr had stabbed Yazzie because she saw Adam Karr carrying a knife earlier.
Lee described the knife a dark blade with a light handle and said she spotted it in Karr's hand behind his back.
"I said to him, 'Give me the knife. What are you going to do with that?' " she testified. "He told me, 'If that kid touches my brother, I'm going to stab him.' "
Later, she said, as Yazzie lay bleeding, Lee asked Adam Karr if he had followed through.
"He said, 'No,' " she said. "But there was blood all over [Karr's] shirt, all over all of their shirts."
Defense attorney Richard Mauro tried to poke holes in witness testimony by pointing to inconsistencies between what the teens told police in the days after the party and what they told the jury Thursday.
He also emphasized Yazzie's misbehavior and refusal to leave when asked in an attempt to prove that Karr had acted to defend himself, his brother and his home.
The defense and prosecution are expected make their final arguments to the jury Friday.