Lou Kilzer, who co-authored a Pulitzer Prize-winning investigation for the Star Tribune in 1989 that exposed a scandal at the St. Paul Fire Department, died on March 27. He was 73.

He suffered from various ailments and was in hospice care when he died in Colorado Springs, according to his family.

Kilzer and fellow Star Tribune reporter Chris Ison won U.S. journalism's top award for a two-part series that connected men who profited from suspicious fires in St. Paul to Fire Chief Steve Conroy who tolerated shoddy fire investigations and allowed firefighters to moonlight for a firm that represented alleged arsonists in fire insurance claims. The reporting team won the Pulitzer in 1990.

It was Kilzer's second Pulitzer. He was one of three reporters to win the Pulitzer's public service award for the Denver Post in 1986 for an investigation that found the number of children abducted in the United States was far less than the claims of national campaigns around missing children.

"He had a real moral compass," said his wife, Elizabeth "Liz" Kovacs. "He was so curious about everything. He had a way of interviewing people and getting them to trust him. He always wanted to expose corruption and malfeasance, which is what he did during his whole career."

Kilzer was born in Cody, Wyo., in 1951. He overcame dyslexia to become Wyoming's high school debate champion and graduated cum laude from Yale University with a philosophy degree.

In a journalism career of more than 40 years he worked for Denver's Rocky Mountain News and Denver Post, at the Star Tribune from 1987 to 1994, and the Pittsburgh Tribune-Review. He was editor-in-chief at the JoongAng Daily, the Korean-language news section of the South Korean edition of the New York Times. He wrote two books about World War II and two novels.

His son, Alex Kilzer, of Denver, said he had fond memories of living in Minnesota and family trips to the Boundary Waters Canoe Area Wilderness and Lake Superior.

"We loved Minnesota," Kovacs said. "We lived in Plymouth. He had an offer from the Washington Post but chose the Star Tribune because he thought it would be better for our family."

Lou Kilzer's daughter, Xanthe Kilzer, of Ripton, Vermont, recalled sitting around the dinner table where "he would share exciting tales of what he uncovered." Once, on take-your-daughter-to work-day, he took her to a murder trial. "I was hearing the brutal testimony. I was kind of in a daze, thinking this is the life of my dad," she said.

Ison, later a journalism professor at the University of Minnesota and now retired, said Kilzer was methodical in his reporting, spending months following paper trails and records. He carried a large briefcase to confrontational interviews, Ison said, pulling out documents if he believed the person he was interviewing was lying or obfuscating.

"It would force people to be more forthcoming, because they had to worry about how much Lou already knew," he said.

John Ullman, a retired Star Tribune editor, oversaw the St. Paul fire stories. He called Kilzer the best investigator he ever worked with.

"He knew that the most important thing was to get everything factual and to weed out those things that you're not sure of," Ullman said.

The St. Paul fire investigation started as a gambling probe, Ullman said. "These guys came to me after two months and said we're on the wrong investigation, it should be an arson investigation. They were right. They had documents from the get-go."

.A memorial program is planned in Denver, but details are not complete.

Staff librarian John Wareham contributed to this story.