Man Shot by Kyle Rittenhouse Describes the Encounter on a Kenosha Street

But Mr. McGinniss also offered what could be the defense’s most crucial witness testimony: that he saw Mr. Rosenbaum chase Mr. Rittenhouse into a parking lot, lunge at him and reach for the barrel of his rifle.

“He threw his momentum toward the weapon,” Mr. McGinnis said in court.

Another prosecution witness, Kariann Swart, testified last week that she was the fiancée of Mr. Rosenbaum and perhaps the last person close to him to see him alive, giving an account of their relationship to the jury and describing her anguish at hearing that he had been killed.

On the morning after he was fatally shot, she said, she went to the parking lot and saw the mark on the pavement where he had been slain.

“I put my hand in it, and my hand was wet with his blood,” she said. “I collapsed on the ground.”

But Ms. Swart also gave testimony that concurred with an assertion by the defense that Mr. Rosenbaum was behaving strangely in the hours before he was killed.

She said that on the day of the shooting, Mr. Rosenbaum was released from a hospital and that he was taking medications for bipolar disorder and depression. When Mr. Rosenbaum visited her at the motel where she was staying, Ms. Swart said, she had specifically told him not to go to downtown Kenosha, where the unrest had been occurring for several nights in a row. He went anyway, carrying a small plastic bag of items from the hospital, she said.

Jason Lackowski, another prosecution witness and one of the armed men who was in Kenosha that night with the goal of protecting property, told the court last week that Mr. Rosenbaum was “a babbling idiot,” downplaying the threat that Mr. Rosenbaum might have posed to Mr. Rittenhouse.

But he also testified that in the minutes after the shootings, he found Mr. Grosskreutz’s pistol lying on the street and emptied its chamber.

Dan Hinkel contributed reporting.