They call him “the plagiarism hunter.” He calls himself “meticulous” and an “addict.”

However he is characterized, in German-speaking countries where titles are important signals of social standing, Stefan Weber is the undisputed terror of academics, politicians, celebrities and a panoply of other potential culprits.

Weber, an Austrian communications professor, has ended the careers of several people and made life difficult for many others. And what started as a hobby has now developed into a business with five freelance “collaborators”, as he calls them, working with him to reveal the misdoings of lazy, sloppy or downright sneaky writers.

His latest target: Annalena Baerbock, the Green Party candidate to replace Angela Merkel as German chancellor in elections this month.

Weber, 51, got started on what would become his life’s work in 2005, when he himself was plagiarized by a German theologian, Joachim Fels, who explained that his failure to acknowledge Weber’s work properly in his doctoral dissertation was the result of an editorial mishap. He seemed to think that would settle the matter, but he did not fully appreciate whom he was dealing with.

Weber’s public complaint ultimately triggered a university investigation revealing that 86% of the first 100 pages of Fels’ dissertation was plagiarized from Weber’s work. The fraud was covered prominently in major news media outlets; trailed by a German TV crew, Weber even door-stepped a perplexed Fels, who was ultimately stripped of his doctorate.

In the intervening years, armed only with commercial software and a nearly photographic memory, Weber has gone after a variety of prominent figures, including, most recently, Baerbock.

Following allegations that she embellished her CV, Weber ran her newly published book, “Now: How We Renew Our Country,” through Turnitin and other plagiarism-detection programs. It marked at least 12 passages as almost identical with other sources.

“Willful deceit,” said Weber, who once worked as a tabloid journalist and who publicized his findings in his blog and through numerous interviews with major news organizations in Germany and Austria.

As the issue played out in front-page articles, experts cautioned against applying standards for doctoral dissertations to a short nonfiction book by a politician. Many saw a concerted campaign to discredit a highly accomplished woman, while others wondered if the far-right had bankrolled Weber’s research. (He said it did not.)

Still, the episode strengthened a sense of Baerbock as “dubious and sloppy,” Weber said. The number of passages in the book found to be cribbed from blogs, news columns, books and the Greens’ election program has since grown to more than 100. She led the polls in the spring, and her support has since dropped to less than 20 per cent, though the plagiarism scandal is not the only factor.

Critics describe him as a persnickety crusader who takes pleasure in character assassination. Even his supporters acknowledge that his drive to hold writers, academics and others to the highest standards can be vexing.

“He always wants to be the best, and he also demands that of others,” said Peter A. Bruck, a former professor at the University of Salzburg who was an academic mentor to Weber.

Invariably, those who fall short of his expectations will hear about it. When he discovered that his children’s after-school center had plagiarized its “pedagogical concept,” he promptly chastised school officials.

“I know when I’m annoying people with my meticulousness,” Weber said over lunch at an Italian restaurant near his office in a scruffy industrial district on the outskirts of Salzburg, Austria. When he is not fasting to stave off the diabetes his doctor predicted a decade ago, he typically enjoys pizza alla diavola, though on this occasion he settled down to a pasta dish while explaining the business side of things.

That consists of investigating academics’ publications, court experts’ opinions and books, for which he bills as much as $400 an hour. But the bulk of his clients typically fall into two categories: men seeking to discredit their ex-wives amid or after a divorce (but never vice versa) and people trying to undermine their neighbors’ credibility in nasty disputes over property lines.

He said he now receives about 50 inquiries a month and that people have begun sending him tips on big cases like the one he mounted against Christine Aschbacher, the Austrian labor minister who stepped down in January after a plagiarism scandal.

“It’s a gold mine,” he said of Austrians’ schadenfreude.

Weber took an odd life route to his current station. Born in Salzburg to a strict and controlling office clerk father who checked his school bag each evening and a mother who worked as a homemaker, young Stefan Weber showed early signs of being a math prodigy.

“May you remain humble in triumph,” a teacher cautioned the 11-year-old Weber. He excelled in most subjects, with physical education being the clear exception. Even these days, when his current partner, Birgit Kolb, hikes in the Alps, Weber opts for the cable car for the climb to the top.

As a student at the University of Salzburg, Weber realized that the triumph his teacher had foreseen long ago was not going to be found in math. Despite his prodigious memory, he was unable to follow the university math professors and instead turned to “the idiot degree everyone studies: communications.”

Communications was a breeze, and Weber went on to teach at eight universities of applied sciences in Austria and Germany, always vying for tenure. He never attained it.

At 37, Weber moved to Dresden, Germany, where his partner at the time worked as a civil servant. While helping to care for their two children, Maximilian and Anna, he taught at universities and worked as a communications consultant.

He also published books critiquing new media and continued to work with Bruck, who still lauds Weber’s intellect and ambition but has little patience for his new career. “From a useful tracker, he transformed into an illegitimate detractor,” he wrote in a 2007 op-ed rebuking Weber for accusing Johannes Hahn, then Austria’s science minister, of plagiarism. (Hahn was eventually cleared of the accusation.)

In 2014 Weber returned to Salzburg, splitting with his former partner the following year.

Most of those he has named and shamed have neither lost their titles nor jobs, Weber said, pointing to Hahn, who went on to become a European Union commissioner. This year, however, when he exposed “plagiarism, wrong citations and poor knowledge of German” in the academic work of Aschbacher, she stepped down within two days.

For more than a decade, Weber promoted plagiarism as a discipline worthy of publicly funded research, but it was only with the Aschbacher case that the government began to take notice. “Only since politics has been hit,” he said, “has politics become interested.”

Now, with government funding, he is evaluating how Austria’s universities deploy plagiarism-detection software and is creating a Wiki that is to become the ultimate guide to proper sourcing, quoting and referencing. Eventually, he said, he wants to raise standards so high that he puts himself out of work.

But for now, he needs to scan and digitize the dissertations of two high-ranking civil servants. Weber picked up the bound volumes from the passenger-side floor of his navy blue Volkswagen and noted that they were written in the aughts, a time when plagiarism flourished.

“That’s already making me suspicious,” he said with a mischievous grin.