A timely phone call changed the trajectory of lawyer Stewart Walz’s career.

Less than a week before he was scheduled to begin a job in August 1980 at a Utah law firm handling tax cases, U.S. Attorney Ron Rencher called to offer him a position as a federal prosecutor.

Walz decided to forgo private practice and instead spent decades at the U.S. Attorney’s Office in Salt Lake City prosecuting cases, many of them white-collar crimes. Over the years, he also served as a teacher and mentor to lawyers, holding classes on legal topics and taking calls from attorneys throughout the country who had questions on all sorts of issues.

And after nearly 42 years in government service, including a four-year stint as an attorney for the Internal Revenue Service, he has no regrets about his decision.

“This was the job for me,” said Walz, 66, who became the office’s senior litigation counsel in 1999 and retired last week. “If I was put on Earth to do something, it was this.”

His fellow attorneys back up that assertion, saying Walz excelled as a prosecutor because of his legal expertise and excellent courtroom skills, as well as his extraordinary memory and mastery of the rules governing the introduction of evidence in federal trials.

Sam Alba, who also joined the U.S. Attorney’s Office as a prosecutor in 1980 and prosecuted cases with Walz, praised his former colleague’s ability to handle extremely complex matters.

Alba cited as an example the prosecution in the 1980s of multiple defendants accused of operating a Ponzi scheme by soliciting investments in the Independent Clearing House Company and Universal Clearing House Company, then paying fictitious profits to the early investors with money deposited by later investors. The trial in the case — which involved 5,300 investors who gave the companies $30 million, according to court documents — lasted five months and resulted in six convictions and three acquittals. (One conviction was overturned on appeal.)

“It’s going to be a great loss to that office because he has a wealth of knowledge and a wealth of experience,” Alba, a former U.S. magistrate judge who now works in private practice, said of Walz’s retirement.

U.S. District Judge Tena Campbell said Walz mentored her when she was a federal prosecutor and is a “wonderful attorney.” And U.S. Attorney for Utah John Huber described him as “an encyclopedia on the law.“

“Stew Walz is one of the most accomplished trial attorneys in the history of the federal court in Utah,” Huber said.

After earning a bachelor’s degree in history from the University of South Dakota and a law degree at Vanderbilt University, Walz started work in 1976 as chief counsel for the IRS Salt Lake City office. Then he got the job as an assistant U.S. attorney.

The office was small when he started, Walz said, and prosecutors handled all kinds of civil and criminal cases. From the beginning, he found the work interesting, with no two cases the same.

Walz said he considers the clearing houses fraud case and the slayings on the Navajo Indian Reservation in December 1987 of two tribal police officers who were breaking up a bonfire and beer party as two of his most important cases. The officers — Roy Lee Stanley and Andy Begay — were shot and transported to a remote location near Lake Powell, where they and their vehicles were doused with gasoline and set on fire.

Four men went on trial in 1988 on first-degree murder charges in federal court in Salt Lake City in the deaths, and Thomas Cly and Vinton Bedoni were convicted and sentenced to life in prison. The jury could not agree on a verdict for Ben Atene and a mistrial was declared; he was found not guilty in a second trial. Charges were dropped against the fourth defendant, Marquez Atene, during the trial for lack of evidence.

Walz’s specialty became white-collar crime, including securities and commodities fraud, Ponzi and other scams. His high-profile cases include prosecutions of real-estate investor Rick Koerber, former ClearOne Communications CEO Frances Flood, Kirk Koskella of Anglo-American Investment and businessman Gary Sheets.

Not all of his cases that went to trial ended with a jury returning a conviction, but, Walz said, “That’s the genius of our system, that ultimately the people decide.”

Fraud still remains a problem in Utah despite the prosecutions and publicity about the cases, according to Walz.

“Affinity fraud [characterized by a bond of trust between fraudster and victim] and white-collar fraud seem to never go away,” he said, adding that “there is no end to Ponzi schemes.”

(Trent Nelson | The Salt Lake Tribune) Assistant U.S. Attorney Stewart Walz is retiring after 41 years of service in the federal government. Most of his career was spent prosecuting white-collar crime. Salt Lake City, Tuesday, Feb. 27, 2018.

Carlie Christensen, a former acting U.S. attorney for Utah, said Walz “lives a case” and has a gift in the courtroom. She said a “phenomenal memory” and his knowledge of the Federal Rules of Evidence are among the reasons for his success.

Brett Tolman, who was Utah’s U.S. attorney from 2006 to 2009, agreed, saying Walz’s memory and ability to utlitize the evidence rules are “second to none.”

Lawyers will focus on the questions they’re going to ask, Tolman said, but the rules of evidence guide what can and cannot be done in court and “when you master those, you become master in the courtroom.”

“He makes it look easy,” Tolman said. “You watch Stew Walz in trial and you would think it is the easiest thing in the world to try a case.”

In addition to prosecuting cases, Walz has been sharing his knowledge with other attorneys. He helped develop curriculum for the National Advocacy Center, a Department of Justice training facility in South Carolina, and spent two years there teaching classes. He also has given numerous lectures on evidence rules, white-collar crime and other topics at various seminars.

Walz finds plenty to do to fill his spare time. A South Dakota native, he learned to ski three years after he arrived in Utah and became so adept at it that he worked as a part-time skiing instructor at Snowbird Ski & Summer Resort for 16 years. He also is an avid golfer and a big movie fan.

In addition to golfing and skiing, Walz said his retirement plans include traveling with his wife, Colleen.

Christensen said everyone can be replaced, but in Walz’s case, it may take more than one person to fill all of his roles in the office.

“I think he absolutely is one of the best trial attorneys in our office and probably in the legal community,” she said.

(Trent Nelson | The Salt Lake Tribune) Assistant U.S. Attorney Stewart Walz is retiring after 41 years of service in the federal government. Most of his career was spent prosecuting white-collar crime. Salt Lake City, Tuesday, Feb. 27, 2018.