The brother of figure skater Nancy Kerrigan is asking a judge to dismiss a manslaughter charge against him in the death of their 70-year-old father, who prosecutors say was stricken after a violent clash between the two.

Prosecutors said Mark Kerrigan was in a drunken rage during a Jan. 24 argument with his father, Daniel Kerrigan, when he grabbed his father around the neck, fracturing his larynx. A state medical examiner said the cause of death was "cardiac dysrhythmia" — a loss or interruption of a normal heartbeat that can lead to cardiac arrest.

Kerrigan's family has said Daniel Kerrigan died of a long-standing heart condition and that his son is not responsible for his death.

Kerrigan's lawyers have filed a motion to dismiss the charge in Middlesex Superior Court and will argue it before a judge Thursday afternoon.

In the motion, attorneys Janice Bassil and Henry Brennan said prosecutors presented no evidence to the grand jury to show that the altercation was the cause of Daniel Kerrigan's death. They said a medical examiner told the grand jury that Daniel Kerrigan had significant blockage of three of his major coronary arteries and an enlarged heart, a condition his son did not know about.

"His family, including the defendant, had no knowledge that he had a coronary disease or that his heart was so damaged," they wrote in the motion.

"Mark Kerrigan's actions did not cause his father's death. His father died of a heart attack that would have happened more likely sooner than later."

Kerrigan's defense also argues that prosecutors failed to call Mark Kerrigan's mother, the only witness to the fight, and exaggerated her level of blindness to the grand jury. Brenda Kerrigan is legally blind but can see across short distances, the defense lawyers said.

Brenda Kerrigan told authorities she saw her husband and son pushing each other, but did not see any other physical interaction between them.

Kerrigan's lawyers also argue that Mark Kerrigan was "so highly intoxicated that he could not possibly waive his Miranda rights in a knowing and voluntary manner."

Police have said Mark Kerrigan and his father were arguing over whether the son could use the family phone.

"He said he struggled with his father and put his hands around his father's neck and his father fell to the floor," the arresting officer wrote in a report.