Defense Witness In Van Dyke Trial Says Laquan McDonald Tried To Stab Him

CHICAGO (CBS) -- On the trial's seventh day, Chicago Police Officer Jason Van Dyke's defense team presented evidence for a third day, though it's still unclear if the officer will testify on his own behalf in the shooting death of 17-year-old Laquan McDonald.

One of the officers who was at the scene of the shooting on Oct. 20, 2014, said McDonald appeared "deranged," and she believed he might have been holding a gun, but later learned it was a knife.

The defense tried to show McDonald was on a violent crime spree the night he was shot, and that Jason Van Dyke was forced to fire.

The man who first dialed 911 to report a teen breaking into trucks testified about his encounter today using an interpreter.

"He pulled out a knife and he wanted to hurt me," Rudy Barillas said. "He came towards me and he tried to stab me."

Chicago Police officer Leticia Velez testified she saw a deranged-looking Laquan McDonald walking down the street with a shiny object.

"I'm trying to say, it looks like he has a gun, just be careful, he's holding something by his side," Velez said.

The officer testified her concern was great enough to cause her to draw her gun.

A police academy instructor told jurors officers are trained to use deadly force when warranted in certain situations.

Another witness who took the stand today, a Chicago police sergeant who once worked with Van Dyke, told jurors about a weapon police were warned about in 2012 described as a knife with a .22-caliber revolver in its handle.

Sgt. William Schield also acknowledged he's never recovered a knife with a revolver hidden inside.

Closing arguments are expected to begin next week.

Here's a rundown of what happened in court today: 

1:32 p.m.

Wednesday's final witness, Dr. Jeremy Slayton, a trauma surgeon at Mt. Sinai Hospital, testified about attempts to save Laquan McDonald when he arrived in the emergency room. He said McDonald did not have any vital signs when he arrived, and he tried massaging McDonald's heart. When he opened McDonald's chest, he saw a bullet wound to his pulmonary artery, and said the teen had only a 1 percent chance of surviving that kind of catastrophic injury.

"If he had been shot with that injury right in front of us his chances of survival are very low," Slayton said.

1:15 p.m.

Defense attorneys called police academy instructor Yolanda Sayre to the stand. Sayre, an attorney, teaches officers about the legal justifications for police use of force, and Van Dyke's defense says he was in her class when he was in the academy.

11:55 a.m.

Cook County Juvenile Detention Center employee Jackie Alexander testifies about an encounter with McDonald in 2014, when he refused to get into his cell. She said McDonald claimed he would  "put a slug in the judge's head."

11:45 a.m.

Chicago Police Sgt. William Schield testified about a safety alert that went out in 2012, warning officers about a so-called "knife-gun," a knife capable of firing bullets. On cross-examination from prosecutors, Schield acknowledged he never recovered one in 27 years on the force, and doesn't know of any other officers who have.

11:35 a.m.

Truck driver Rudy Barillas, whose 911 call on Oct. 20, 2014 set off the series of events that led to Van Dyke shooting McDonald, testified Wednesday, with the assistance of a Spanish language interpreter.

Barillas testified he confronted McDonald at a truck yard at 41^st and Kildare, after spotting the teen inside a truck.

"I told him I was going to call the police if he didn't leave," he said.

Barillas said McDonald tried to stab him, so he threw his phone at him, and McDonald came at him again, so he threw a handful of dirt and gravel at him. When Barillas called police, McDonald ran off.

However, Barillas never identified McDonald by name, referring to him only as a "male black" he saw in the truck yard.

On cross-examination, prosecutors made a point of stressing Barillas was able to defend himself from McDonald without needing a gun or police, even when McDonald came within three feet of him.

"So you were able to fend off this man with a cell phone and a hand full of rocks, right?" Assistant Special Prosecutor Joe Cullen said.

"Yes," Barillas said.

10:37 a.m.

Wednesday's first witness is Chicago Police Officer Leticia Velez, who responded to the scene on the night of the shooting. She said McDonald appeared "deranged," and was not responding to any of the police activity around him.

"We had lights, we had sirens, and he was not looking our direction," she said. "There was nothing that was fazing him."

Velez said she noticed a "shiny object" in McDonald's hand, and told her partner she thought he might have a gun.

She also said the dashboard camera video of the shooting does not show her view of McDonald.

"It doesn't show his face. It doesn't show the look in his eye," she said.

• Murder
• Trial
• Crime