Former special counsel Robert Mueller declined to pursue President Trump’s tax returns as part of his Russia investigation, according to a forthcoming book.

Under questioning by lawmakers last summer, Mueller repeatedly said, “I’m not going to get into that.” He did acknowledge that he was not instructed by anyone not to dig through Trump’s financial information after the president said early on in the investigation that Mueller could be crossing a “red line” by doing so. His report, released with redactions, didn’t mention it.