CBS (CHICAGO)–The civil trial of police officer Robert Rialmo continued Monday, when his partner told jurors he feared for his own life moments before Rialmo shot and killed Quintonio LeGrier and neighbor Bettie Jones.

CBS 2’s Jim Williams Rialmo reports from the Daley Center, where Rialmo is at the center of a wrongful death lawsuit.

“I thought my head was going to get split open,” Officer Anthony LaPalermo told jurors.

He said on December 26, 2015 that he and Rialmo were ambushed by LeGrier, who was brandishing a baseball bat at his father’s home.

“I knew if I didn’t get away I was probably dead,” LaPalermo said. “He sprinted down the stairs and attacked us with a bat—there was no time to even say a word.”

Rialmo fired the shots that killed 19-year-old LeGrier.

Palermo quoted LeGrier’s father, who yelled four or five times to the officers, “You did what you had to do.”

This morning, jurors heard a different take on the shooting in video testimony from consultant and former South Florida cop Charles Drago. He was hired by the LeGrier family’s attorneys.

Drago said the shooting was ‘not consistent with most police practices.

He also testified that Rialmo was likely standing far enough away that he shouldn’t have had to shoot LeGrier.

“He doesn’t have to wait to be hit before using deadly force, right?” city attorney Brian Gainer asked.

“No, but an officer does have to wait for a threat,” said Drago.

Drago told jurors a cluster of bullet casings from Rialmo’s 9mm gun indicated he was standing on the walkway when the shots were fired.

LeGrier’s mother, Janet Cooksey, also took the stand Monday. She spoke in a barely-audible voice and told the court she missed her son.

Cooksey recalled driving LeGrier to his father’s house on Christmas morning after he “broke and unspecified household rule,” she said.

As they parted, Cooksey testified her son told her, “You’ll remember this day.”

He was dead less than 24 hours later.

Last week, Quintonio’s father told the court his son appeared to be angry about something in the early morning hours of December 26 before police were called to the home.