During a years-long court fight over an idiosyncratic copper heiress' $300 million estate, a New York criminal investigation quietly examined how she and her finances were being looked after, though no one was ever charged.

The Manhattan district attorney's confirmed Thursday that it has ended its investigation into Huguette (OO'-gheht) Clark's circumstances. It's not immediately clear when.

Spokeswoman Erin Duggan says "the case is closed, barring any new information." NBCNews.com first reported the development.

Clark died at 104 in 2011. Her father was Montana copper baron and U.S. Sen. William A. Clark, who founded Las Vegas.

She elected to spend her last 20 years in a hospital, despite mostly being well enough to live in her Fifth Avenue apartment or mansions in Santa Barbara, Calif., and New Canaan, Conn.