The Kerrigan Curse: Nancy Kerrigan's Brother in Jail

Jan. 26, 2010— -- Autopsy results regarding the death of former Olympic figure-skating star Nancy Kerrigan's father could determine whether the charges filed against her brother Mark Kerrigan expand from assault to homicide.

Mark Kerrigan, 45, remains in jail today, a day after openly sobbing in the courtroom as he pleaded not guilty to charges of assaulting an elderly person. Daniel Kerrigan died Sunday in his Massachusetts home after the two scuffled during an argument over a phone call.

"After the autopsy this case could be considered a homicide, which means the death was caused by a person," ABC News chief law and justice correspondent Chris Cuomo said today on "Good Morning America." "If authorities are able to ... connect what Mark did to his father, the choking, to the death, then he could get hit with a homicide charge."

Mickey Sherman, a Connecticut criminal defense attorney who is not working on the case, said today that even if prosecutors go for a murder charge, the best they can hope for is a manslaughter conviction because there was seemingly no intent to kill.

"Of course it's his fault," Sherman said of Mark Kerrigan. "He set off this chain of events."

Though prosecutors often "over charge" defendants in these types of cases expecting a plea deal, Sherman said the family's high-profile name alone could lead to a murder charge for Kerrigan.

"If they do it, it'll be because of public pressure," he said.

Mark Kerrigan was held on $10,000 bail despite his lawyer's request to a judge to release him on a "personal promise" so he would be able to grieve with his family.

"It makes you so sad to think an argument potentially over a telephone could have led to this," ABC News sports contributor Christine Brennan told "Good Morning America" today.

But the tragedy could significantly worsen if police determine that Mark Kerrigan's alleged assault on his 70-year-old father led to his death, whether from his injuries or from a heart attack.

Both the timeline and the causation will be key elements in making that determination, Cuomo said.

"You're going to have to show that between the time that the choking was done and the death happened, the heart attack, as it's alleged right now … that that was the cause for it."

Making that case would be "not that simple," Cuomo said. "A charge is more likely than a conviction for that in this case."

Mark Kerrigan's lawyer made a point of noting that the brother of the famous Olympic figure skater suffered from post-traumatic stress disorder as a result of his time in the military. But Kerrigan also has a lengthy history with the law and has served time in prison.

There was no word on when the autopsy results were expected, and Kerrigan is due back in court at the end of February.