Norfolk Southern has opened an investigation into allegations of potential misconduct by CEO Alan Shaw, over claims that he was involved in an inappropriate workplace relationship.

The Atlanta-based railroad company said on September 9 that it had hired a law firm to carry out an independent probe. Shaw’s alleged behavior was inconsistent with company policy and its code of ethics, Norfolk Southern said. It didn’t specify the nature of the alleged actions.

CNBC, citing people familiar with the matter, reported earlier on the alleged relationship and said that the investigation was in its early stages. Shaw didn’t return CNBC’s calls or text messages seeking comment, according to the report.

Norfolk Southern didn’t immediately respond to requests for comment from Bloomberg News outside regular business hours.

Shaw has been the CEO of Norfolk Southern since May 2022.