PEORIA, Ill. (AP) — Caterpillar says it believes that a search warrant executed by federal authorities on Thursday at its facilities concerns “export filings” related to its Switzerland subsidiary CSARL.

In a statement Thursday after federal agents appeared at its Peoria, Illinois, headquarters and other Illinois facilities, Caterpillar says the issue it concerns was first disclosed in a 2015 filing with the Securities and Exchange Commission.

At that time, the Caterpillar said the SEC had notified the manufacturer that it was conducting an informal investigation relating to CSARL, and asked the company to preserve relevant documents.

Caterpillar spokeswoman Corrie Heck Scott said in an email that the company is cooperating with law enforcement.