CBS (CHICAGO)–Today in court, the father of Quintonio LeGrier described the moments before and after Officer Robert Rialmo shot and killed his son.

CBS 2’s Jim Williams reports from the Daley Center, where the murdered man’s father, Antonio LeGrier, on Thursday testified in the trial of Chicago Police officer Robert Rialmo.

Antonio LeGrier spent hours on the witness stand—at times breaking down in tears as he described his son’s last hours alive.

He said he had tried to protect himself from his son.

“I loved my son very much,” he said.

Antonio LeGrier described roller skating and playing cards with Quintonio.

But he also said Quintonio appeared to be angry about something in the early morning hours of December 26, 2015—the day Officer Rialmo responded to a domestic disturbance in the 4700 block of West Erie.

That’s where the fatal shots were fired.

While on the witness stand Wednesday for the second occasion, Rialmo recalled hearing a rumbling, then saw Quintonio barreling down the apartment building stairs holding a baseball bat over his head.

When asked by city lawyer Brian Gainer what he thought, Rialmo replied, “I thought he was going to take my head off.”

Antonio LeGrier told the court he had used a two-by-four to block his bedroom door in their West Side home.

It was 4 a.m. when Antonio LeGrier was awakened by a loud banging on the bedroom door.

He quoted Quintonio as saying “no one is going to push me around anymore.”

“The only word I could think of was ‘rampage,’” Antonio LeGrier told jurors.

The father called 911… and asked neighbor Bettie Jones to call 911.

Jones answered the door when police arrived and told the officers the disturbance was “upstairs,” according to court testimony from Wednesday.

LeGrier recalled going down the stairs and hearing gunshots, and then seeing his son face down between the vestibule and Jones’ apartment.

Jones had been accidentally fatally shot by Rialmo.

LeGrier said he did not see the shooting itself.

“I was cheated out of my ability to help my son,” he said as he sobbed in court.

LeGrier  revealed to the court that his son lived not at home, but with a legal guardian, while he was growing up.

Quintonio’s mother is also expected to testify.