BERLIN — He told the story of a Syrian boy who believed he had helped start the country’s civil war with a prank. He profiled an American woman who traveled around the United States to watch executions. He brought to life, in astoundingly granular detail, the anguish of a would-be suicide bomber in Iraq.

Claas Relotius, a star writer at Der Spiegel, Germany’s most respected newsmagazine, won many awards for his reporting on the most important stories of the day.

Except, it turns out, much of it was invented.

Der Spiegel fired Mr. Relotius and published a lengthy apology to its readers this week. But the failure of a magazine long considered the leader in Germany for hard-hitting investigations could have cascading consequences for the news media, analysts and senior journalists said.

“Spiegelgate,” as it has been dubbed on social media, is one of Germany’s biggest postwar journalism scandals, potentially spanning seven years and many dozens of articles. Coming at a moment when public trust in journalism is already low, it could hardly have arrived at a worse time.