ROLLING MEADOWS (CBS) –Jurors in a suburban courtroom found a man guilty this afternoon in the stabbing deaths of three members of his fiancée’s family.

D’Andre Howard’s defense team argued insanity in the 2009 attack that left Laura and Alan Engelhardt and Marlene Gacek dead and Shelly Engelhardt seriously wounded.

Prosecutor Maria McCarthy was asked what she thought of Howard’s testimony that he heard noises in his head.

“I thought it was ridiculous. I thought D’Andre’s testimony was ridiculous and clearly the jury did too,” said McCarthy.

A family spokesman said afterward that justice was served and the mandatory life sentence will provide closure.

Jeff Engelhardt says his family never bought Howard’s insanity defense. He said the verdict is helping them move forward once again.

“A lot of emotions….just a lot of relief,” said Jeff Engelhardt.

Defense lawyers said the judge denied them the ability to present their full case and will appeal.

“We are disappointed that the jury wasn’t really able to get all of the information that we feel they should have gotten about D’Andre’s background and his mental health history,” said defense attorney Deana Einstock.

Howard’s mother could manage only dry heaves as she left the courthouse.