Nancy Kerrigan's brother called "mean, drunk son"; jury gets manslaughter case in father's death

(CBS/AP) WOBURN, Mass. - After hearing prosecutors describe the brother of Olympic skater Nancy Kerrigan as an "angry, mean, nasty, drunk son" who killed his father, the jury in Mark Kerrigan's manslaughter trial began deliberations just after noon on Monday.

PICTURES: Nancy Kerrigan Family Tragedy

Mark Kerrigan, 46, is charged in the 2010 death of his 70-year-old father, Daniel Kerrigan, at the family's home in Stoneham, just north of Boston.

The Kerrigan family has supported Mark, insisting that he is not responsible for Daniel Kerrigan's death. Nancy Kerrigan has been in court every day of the weeklong trial and has often comforted her mother during difficult testimony.

Kerrigan's lawyer, Janice Bassil, countered the prosecution version of events that led up to the elder Kerrigan's death, by citing medical testimony from experts on both sides who said that Daniel Kerrigan had 85 percent to 100 percent blockage of three main coronary arteries.

She also cited testimony from defense experts who said Daniel Kerrigan's fatal dysrhythmia likely began before he had any physical interaction with his son.

Members of Daniel Kerrigan's family testified that he had slowed down physically and appeared tired and grayish in color in the weeks before his death.

Bassil cited Brenda Kerrigan's testimony that she saw her husband grab her son by the shoulders, then saw her son with his arms around his father's waist. She testified that her husband then fell to the floor "like a feather coming right out of the sky."

"She did not see Mark grab his father by his neck. She did not see him push him to the floor," Bassil said.

Assistant District Attorney Elizabeth Keeley told jurors that although Daniel Kerrigan had been diagnosed with coronary artery disease seven years earlier, he had remained physically active, mowing his lawn, plowing his driveway and using a chain saw to chop up a tree limb in the months before his death.

She challenged the description of the fight by Kerrigan's mother saying, "you know, ladies and gentlemen, that it would take a lot more than a bear hug to bring that man down," Keeley said. "It took this defendant - an angry, mean, nasty, drunk son of his - to take Daniel Kerrigan down, to end his life."

Mark Kerrigan is charged with involuntary manslaughter and assault and battery on a person 60 years or older causing serious bodily injury. The manslaughter charge carries a sentence of anywhere from probation to 20 years in prison, while the assault and battery charge carries a maximum of 10 years.

COMPLETE COVERAGE OF THE NANCY KERRIGAN FAMILY TRAGEDY ON CRIMESIDER