Terrica and Alina Powell, the parents of Jody Powell, have asked a judge to appoint a neutral third party as conservator, The Salt Lake Tribune reported Thursday.
Police considered Jody Powell a person of interest in the December 2009 disappearance of his wife. He killed himself and his two sons, ages 5 and 7, in a February 2012 fire at a house in Graham, Wash.
The body of Susan Powell has not been found and she has not been declared dead.
Her father, Chuck Cox, was appointed conservator of his daughter's estate and a trust in January. Until Susan Powell is declared dead, a conservator can only pay taxes on the couple's Utah home, but cannot sell it.
Removing Cox could make Jody Powell's family eligible for $3.5 million in life insurance policies, the Tribune said.
Joshua Lee, the Powells' attorney, told District Judge L.A. Dever, they received notice of Cox's appointment after the fact and that Cox had no authority to remove them as trustees by changing the terms of the trust.
Cox's attorney, Donald Reay, said the trust's bylaws did not specify what to do if Susan Powell went missing, but Utah law permitted her father to be conservator.
Dever said he would issue an opinion at a later date.