Three of the country's largest animal welfare groups on Monday accused the trustees of Leona Helmsley's estate of a "scheme to deprive dog welfare charities" of their stake in the real estate baroness' fortune. They filed a petition in Manhattan Surrogate Court arguing that Helmsley, who died in 2007, specified in her will that her multibillion-dollar estate should be used to help dogs, and the trustees disregarded those wishes.

The groups — the Humane Society of the United States, the American Society for the Prevention of Cruelty to Animals and Maddie's Fund — want the court to throw out a judge's February decision that gave the trustees for the Leona M. and Harry B. Helmsley Charitable Trust sole authority to determine which charities would benefit from her estate.

In April, the trustees gave away $136 million to hospitals, foundations and the homeless. They gave $1 million to animal charities, including $100,000 to the ASPCA and groups that train guide dogs for the blind.

The trust, in a statement posted on its Web site, said Helmsley never wanted her fortune just to go to dogs.

"Did Leona Helmsley intend for this charitable trust to focus on the care and help of dogs, rather than people? Absolutely not," the statement said. "Have the trustees of this vast fortune acted improperly and ignored Mrs. Helmsley's instructions? Again, absolutely not."

The hotel heiress, whose fortune had been estimated at $5 billion to $8 billion after her death at age 87, also named her dog as a beneficiary in her will, leaving a $12 million trust fund for the little white Maltese. But a judge whittled that amount down to $2 million.