Haney & Young LLP filed a breach-of-contract suit against Jean Kasem Tuesday in Los Angeles Superior Court, claiming she owes $50,500 in legal bills.
The firm claims it entered a contract on June 5 with Kasem, who they allege ignored subsequent bills.
City News Service reports Kasem has agreed to arbitration.
Court documents obtained by the outlet show the lawsuit was filed to ensure arbitration is nonbinding.
Casey Kasem passed away June 16 at the age of 82 following a battle with dementia and Lewy body disease.
His declining health sparked a bitter family battle over his care and treatment.
In October 2013, Kasem's children with his former wife, actress Linda Myers, as well as Kasem's brother and a business associate, went public. The group held a protest outside Kasem's home, alleging Jean wouldn't let any of them see Casey and had been rebuffed in their efforts for three months.
In May 2014, Jean told a judge that Casey was no longer in the United States, however, he turned up several days later in Washington state.
On June 6, a Washington state court recognized the legal rights of Kasem's eldest children to see their father and gave daughter Kerri full conservator control of his affairs.
Haney & Young initially won a ruling on Jean behalf that same month, when a Los Angeles Superior Court judge ordered the legendary broadcaster to continue to be cared for at the Washington state hospital.
That decision was reversed two days later when the judge authorized Kerri to remove her father from life support.
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