Washington( CNN) What was meant to be a celebratory tour of the Midwest on Thursday turned sour for President Donald Trump when he learned federal prosecutors were looking to question his company's longtime fiscal boss.

For Trump, the news added another unfortunate layer to his growing frustration at the swirling legal issue now clouding both his administration and his business. Trump's mood, people inside the White House say, has grown dark as his longtime fixer Michael Cohen executes a very public breakup. Even as he worked to exude confidence about a roaring economy and handshake deal with Europe, the encroaching difficulties induced for another agony-and-ecstasy week.

“They're dying to see us make a little bit of a mistake, ” Trump lamented Thursday from inside a Granite City, Illinois, steel plant, where he was hoping to exult in positive economic news in front of a supportive crowd. Aides said they coordinated the tour hoping to spotlight policies that have helped boost American manufacturing. Privately, some also concede get Trump on the road is a way to distract him from the persistent drip-drip of the Russia investigation.

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