The mystery of last week’s Caterpillar office raid by various US government agencies may have been resolved, after the NYT reported overnight that a report commissioned by the government, written by an accounting professor at the Tuck School of Business at Dartmouth, has accused the heavy-equipment maker of carrying out tax and accounting fraud.

“Caterpillar did not comply with either U.S. tax law or U.S. financial reporting rules,” wrote Leslie A. Robinson, an accounting professor at the Tuck School of Business at Dartmouth College and the author of the report. “I believe that the company’s noncompliance with these rules was deliberate and primarily with the intention of maintaining a higher share price. These actions were fraudulent rather than negligent.”

CAT spokeswoman Corrie Heck Scott said that the company had not been provided with a copy of the report and declined to comment further. The company has defended its tax strategies in previous years by calling the arrangements prudent and lawful among large United States companies, despite repeatedly falling in hot water with the government over its tax practices which have been a focus of government investigators since a 2014 Senate hearing found that the company cut its tax bill by $2.4 billion over 13 years, moving earnings out of the United States and into a Swiss subsidiary, despite internal company warnings that the strategy lacked a business purpose, other than tax avoidance. Less than a year later, Caterpillar disclosed it received a subpoena from federal investigators seeking documents and information relating to the movement of cash among domestic and overseas subsidiaries, as well as other matters involving its foreign units, including the Swiss entity.

The company has since disclosed in securities filings that the Internal Revenue Service is seeking more than $2 billion in income taxes and penalties on profits earned by the Swiss unit. Caterpillar has said it is “vigorously contesting” the I.R.S.’s proposed increases.