Brandon Haarman, 27, of the 3900 block of North Long Avenue, is accused of killing his father. View Full Caption Chicago Police Department

COOK COUNTY CRIMINAL COURTHOUSE — A developmentally delayed man accused of stabbing his father 13 times with a serrated kitchen knife was acting in self-defense, his attorney argued Thursday afternoon.

Brandon Haarman, whose mother has worked for the Chicago Police Department for 19 years, glanced to the back of a Cook County courtroom, where she sat crying with his sister, as prosecutors laid out the details of the case against him.

Haarman, 27, was arguing with his father in their apartment in the 3900 block of North Long Avenue in Portage Park on Tuesday night when he grabbed a serrated kitchen knife and plunged it into his father 13 times, stabbing him in his chest, face and shoulder, Assistant State's Attorney Heather Kent said.

A neighbor "heard the defendant yelling and then a loud thud," Kent said. The same neighbor later saw Haarman wearing a blood-stained shirt. James Haarman, 53, was found dead on the kitchen floor.

But Theodore Adams, an attorney representing Haarman, called the bloody scene in the Portage Park apartment a "straight self-defense case."

He said James Haarman, known to behave abusively toward Haarman, "came at him, threatened to kill him and knocked off his glasses."

Haarman, he said, has the "mental capacity of a 13-year-old" and grabbed the knife because it was near to him in order to fight off the father.

"Basically, he's a kid," Adams said.

Adams also said that police did not inform Haarman that his father was dead when they questioned him and that he "he was distraught over finding out his father is deceased."

A Cook County judge ordered Haarman held in lieu of $700,000 bond.