Some former federal prosecutors believe a decision to execute search warrants at Caterpillar Inc. indicates that the company hasn’t been forthcoming with the feds, the Peoria Journal Star is reporting.

The newspaper in Caterpillar’s hometown spoke to several former prosecutors in general terms to seek insight into the pending criminal investigation. It emphasized that the former prosecutors to whom it spoke do not have specific knowledge of the government’s case against the company.

Caterpillar is the world’s largest manufacturer of earth moving equipment.

“Investigations like this tend to take years, and the government is often doing things outside of public view,” Renato Mariotti, a former assistant U.S. attorney in the Northern District of Illinois, told the Peoria newspaper. He is now partner with Thompson Coburn in Chicago.

“The government throughout the covert part of the investigation has found things that they believe would be of significant concern, and they have probable cause to believe a crime has been committed,” Mariotti said. “That’s why you would get a search warrant, so you could quickly act.”

In a message to employees late Thursday, Caterpillar CEO Jim Umpleby said the firm has cooperated with investigators regarding offshore tax strategies, but that the investigation may be looking elsewhere, as well.

The newspaper’s full story can be read here.