Joe Rigert, dubbed Minnesota's "most feared and revered investigative reporter" during a long career with the Star Tribune, died Nov. 26 at his home in Minneapolis. He was 91 and had been in poor health, his family said.

Rigert was "one of the most tenacious people I ever encountered," said former Star Tribune executive editor Tim McGuire. "When he got his teeth in, he never let go."

"I do negative stuff," Rigert told Minnesota Monthly in an article about him in 1993. "I'm not out to report that the Boy Scouts met yesterday and sold cookies. I deal with problems, that's my job."

But McGuire said Rigert also cared about the people he covered and the outcomes of his reporting.

Rigert was born in Beaverton, Ore., and earned degrees from the University of Oregon and Georgetown University in Washington, D.C. He was a photojournalist in the Navy and worked for the Oregon Journal and Associated Press before joining the Minneapolis Tribune in 1965.

He became the Tribune's city editor in the 1970s but later returned to reporting, which he found more satisfying than supervising reporters, said former colleague Jim Parsons. He accumulated many state and national awards, including several Premack Public Affairs Journalism Awards from the Minnesota Journalism Center.

With reporter Maura Lerner in 1990, he investigated restraint devices used in nursing homes that had led to 33 deaths in Minnesota, prompting a federal investigation. Two years later, Rigert and Lerner reported that renowned transplant surgeon John Najarian had ignored federal warnings about an experimental transplant drug, leading the University of Minnesota to remove Najarian as chief of surgery.

In 1995, Rigert and Richard Meryhew reported that prominent Duluth businessman Jeno Paulucci had used false and questionable documents to obtain public loans for a new food business. Paulucci struck back with a full-page ad in the Star Tribune denouncing Rigert for "burying his own pet cat alive" years before while euthanizing the dying kitten.

Rigert loved the ad, Lerner said: "He joked that was the first time in his career that he made money for the newspaper."

He had a reputation for being combative and meticulous, checking and rechecking facts. "If you had a disagreement, sometimes it was loud. But he never held a grudge," Meryhew said.

Rigert was a former president of Investigative Reporters and Editors, a national organization, and also served as unit chair for the Newspaper Guild, the union for journalists and others at the newspaper. He retired in 2000.

Rigert wrote four books, including "An Irish Tragedy," on sexual abuse committed by Irish priests, and "Europe on Eight Kids a Day." He and his wife, Janice, raised eight children, including seven who were adopted and of different nationalities.

"He was my hero," said daughter Rebecca, of Brooklyn, N.Y. "He was absolutely behind anything you wanted to do and insisted on following our dreams."

Rigert often interviewed his children about their thoughts "in a playful way," said daughter Marie Silver of Ware, Mass. "It was always, 'What is your passion and what do you want to do with that?' "

Beside his wife and daughters Rebecca and Marie, Rigert is survived by daughters Linda Elrich of Osseo and Anne Muldrow of Minneapolis; sons Douglas and Dominic, both of Minneapolis, and David of St. Bonifacius; brothers Jim of Portland, Ore.; Robert of Naselle, Wash.; Tom of Seattle; David of Rapid City, S.D.; and Vincent of Beaverton, Ore.; sisters Marietta Boyer of Sheraton, Ore.; Suzanne Schoonover of Louisville, Colo.; and Donna Knight of Seattle. Services have not yet been scheduled.

Staff librarian John Wareham did research for this article.