PHOENIX — The unsigned letter arrived at the Arizona Supreme Court in late October 2001.

A professional guardian, the director of a nonprofit Tucson firm, was stealing from his elderly and disabled clients, it alleged.

The court's fiduciary unit sprang into action.

Manager J.R. Rittenhouse went to Tucson, interviewed the firm's employees and dug through court records and boxes of canceled checks.

She discovered that the guardian had taken nearly $3,000 from a developmentally disabled man for an electric bed that was never purchased. The same client paid $1,000 for a fundraising dinner he never attended.

Within two months, the unit had enough documentation to issue an emergency suspension of the guardian's license. The license was later revoked. The unit's work also triggered a criminal investigation by the state attorney general's office, which led to felony theft charges against the guardian involving three clients.

Many experts say that if conservatorship — California's largely unregulated system for protecting adults deemed unable to care for themselves — is to be reformed, the state needs to take several pages out of Arizona's book.

A decade ago, Arizona confronted troubles similar to those detailed in a four-part series published last month by The Times.

Though conservatorship began as a way to help families protect enfeebled relatives from predators and self-neglect, a growing trade of for-profit conservators has taken root in California as the population has aged and families have split up.

Today, about 500 professional conservators operate in the state, caring for at least 4,600 incapacitated adults and managing $1.5 billion in assets.

Though they hold sweeping authority over their clients' lives, no agency licenses conservators or investigates complaints against them. The Times' investigation found that professional conservators often gain legal authority over elderly people without their knowledge or consent, taking control of their lives and finances with jarring speed.

Some conservators neglected their wards, isolated them from relatives and ran up excessive fees. Others used their power over seniors' estates to benefit themselves, their employers or their friends.

The state's swamped probate courts, which appoint conservators and are charged with monitoring their work, overlooked incompetence, neglect and outright theft.

In Los Angeles County, the public guardian's office — founded to act as the conservator of last resort for the indigent — was so chronically underfunded that it turned away most seniors referred to it for help and provided poor service to others.

Elder-law specialists, advocates and researchers acknowledge that there is no single cure-all for protecting California's elderly.

They say the best hope for a remedy lies in a combination of measures, some pioneered by Arizona.

They also suggest that California look far and wide for other potential models: to Florida, which recently installed the country's toughest licensing exam for prospective guardians; to Texas, which has made it harder to start guardianships using provisions meant only for emergencies; and even to Canada, where a broader, better-financed public system for disabled seniors has made for-profit caretakers unnecessary.

"It's a very challenging process," said Terry Hammond, an El Paso attorney who is executive director of the National Guardianship Assn., the main trade group for guardians. Predicting that the push for reform would become a test of political will, he urged California to commit the resources needed to ensure the system's integrity.

If it does, he said, "the Legislature will be able to say, 'We did the right thing for people who needed our help.' "