Details of years of squabbling between family members of shopping mall magnate Mel Simon have begun to emerge in a court battle over the late billionaire's estate.

Attorneys for Mel's widow Bren and Mel's children from a previous marriage took swipes at each other in opening arguments at a Thursday hearing in Hamilton County to determine whether Bren should remain as the estate's trustee. The hearing, the latest step in a bitter battle over a fortune estimated to be worth about $2 billion, was expected to last all day.

An attorney for Bren said his client, who was married to Mel for 37 years, believed a long-simmering dispute was coming to an end after Mel died on Sept. 16, 2009.

She had withdrawn as a candidate for a U.S. Ambassador position to care for Mel after he was diagnosed with pancreatic cancer that June, and opened her Asherwood estate to Deborah Simon and her siblings so they could be with their father in his final days.

"It appeared that peace had returned to the family," said Michael Ciresi, a partner in Minneapolis-based Robbins Kaplan Miller & Ciresi LLP.

Not for long.

In November, Bren received a letter from an attorney representing Deborah and her siblings Cynthia Simon-Skjodt and David Simon, the chairman and CEO of Simon Property Group, asking her to step down as trustee.

Deborah's attorney, Barry Simon, who is not related to the family, argued Thursday that Bren is not qualified or capable of managing the estate. He pointed to a secret recording she allegedly made of trust advisers, her taking of $13 million in an unauthorized advance from the trust, and her history of harsh interactions with Mel's children.

He quoted from several e-mails, including one in which Bren allegedly said of Deborah, Cynthia and David, "I hope they rot in hell."

Ciresi said Bren regrets her harsh words, but that harsh words were said on both sides, and the animosity has not colored Bren's approach to her role as trustee.

He said Bren was holding several e-mails, too, but hopes not to introduce them in court.

"I don't think Mel Simon would have liked to see these e-mails put in the public record," Ciresi said.

Deborah contends her father was suffering from dementia and didn’t understand what he was doing when he revised his estate plan, boosting the share of his fortune going directly to Bren from one-third to one-half.

The changes also wiped out a portion that was to go to Deborah and her siblings from Melvin’s earlier marriage and left charitable gifts stipulated in prior versions to Bren’s discretion.

Bren, who married Mel in 1972, contends the changes fully reflected his wishes.

This story will be updated on ibj.com.