Nancy Kerrigan's family is "deeply disappointed" by a jury's decision to indict the Olympic figure skater's brother on manslaughter charges following his father's death, according to their lawyer.

Mark Kerrigan was arrested on Jan. 24 after his 70-year-old dad Daniel was found unconscious in the kitchen of the family home in Massachusetts. Officials ruled Daniel died from cardiac dysrhythmia after suffering a neck injury during a physical altercation shortly before he passed away.

Mark pleaded not guilty to charges of assault and battery with a dangerous weapon on an elderly person and causing serious bodily injury.

The 45-year-old is now facing another charge of manslaughter after he was indicted for the additional crime by a Middlesex Superior Court Grand Jury on Thursday.

But the Kerrigans are upset by the new development -- and they remain convinced Mark is not to blame for his dad's death.

Speaking on behalf of the Kerrigans, lawyer Tracy Miner tells Entertainment Tonight, "We are deeply disappointed at the continued prosecution of Mark Kerrigan. We disagree with the decision to indict and look forward to the facts being considered by an impartial jury.

"The Kerrigan family continues to believe that he is not responsible for the death of their beloved Daniel Kerrigan. Mark Kerrigan has been living at home supporting and caring for his mother and is in complete compliance with all conditions of his pre-trial release and we see no reason that the situation should change."

The case continues.