Karen Feld, 63, of Washington, said she has a history of brain injuries that cause seizures. She testified that she couldn't control what she was saying when she went into one of her episodes at the penthouse apartment where her aunt's memorial service was being held and where she lived with her brother as a youth.
She said that her brother's guards harmed her by dragging her out of the service and that she eventually needed to have a tumor removed because of their assault and battery.
But the jurors did not agree after a two-week trial in which three security guards contradicted her testimony.
Kenneth Feld, 62, of Tampa, Fla., smiled broadly and hugged his lawyers in response to the verdict. He said afterward that he was happy with the outcome but that he felt it was a shame their feud had to go so far.
"It never should have come to this," Feld told reporters on the courthouse steps, his first comments to the media in the case. "There's no way I ever wanted this to be in the courtroom."
The case is the culmination of decades of estrangement between the Feld siblings, the only children of former circus owner Irvin Feld.
He died in 1984 and passed his ownership of Feld Entertainment and most of his wealth to his son, leading Karen Feld to file her first lawsuit against her brother. She won a settlement from that case and reached an agreement with her brother earlier this year in another suit over their uncle's estate.
This time Kenneth Feld fought his sister all the way through a trial full of drama. On the witness stand, Karen Feld described a tragic family behind the Big Top: She said that both her parents physically abused her; that her mother committed suicide when she was 10 and her brother 9, and that, years later she walked in on her father having sex with her fiance.
Kenneth Feld gave a much kinder portrayal of their family and wept when telling of the death of their Aunt Shirley, who raised the siblings after their mother's death.
"Since Aunt Shirley's shivah was desecrated, this is now probably the closest thing to closure that we will ever have," Kenneth Feld said after the verdict.
Karen Feld left the trial shouting in anger twice after being repeatedly referred to as "Mrs. Feld" although she's never been married. These disruptions led U.S. District Judge Ellen Segal Huvelle to post a court security officer in the courtroom.
Karen Feld said that her hearing the erroneous courtesy title and her subsequently being surrounding by courthouse security guards triggered seizures, and that she was under medical care and unable to return to the courtroom for the final four days, including the verdict.
But she responded in an email to the Associated Press:
"I respect the jury's decision, but I'm disappointed that Kenny got away with bad and malicious behavior at my expense yet one more time," she wrote. "He's nothing but a bully with millions of dollars to hire thugs to assault me and PR pros to detract from the real issues and spin the story his way. I had hoped that the verdict would provide me with a sense of personal safety but that's not the case."
The jury found that Karen Feld had been imprisoned by the private security guards her brother hired, but it also ruled the action had been justified.
"Ken Feld's bodyguards acted properly based on the situation and what they knew," jury foreman Chad Capule said in an interview outside the courtroom. He said days of medical expert testimony showed that Karen Feld clearly had a brain injury and wasn't responsible for her actions at the shivah, but hadn't proved that the guards' handling of her caused her to need brain surgery.
Capule said the most dramatic moments in the courtroom - Kenneth Feld's emotional testimony and Karen Feld's angry departure - didn't influence the jury, saying: "That had nothing to do with the evidence."