Hackers took control of the film company’s computer systems, forcing it to send employees home for the day, according to multiple outlets.

Website The Next Web reported on the incident Monday afternoon, citing a discussion on online bulletin board Reddit in which someone posted images that had appeared on Sony Pictures employees’ computers. The images featured the words “Hacked by #GOP” and referred to “demands” that the company must meet before Monday night in order to prevent the release of sensitive financial documents. The message was accompanied by an image of a skeleton.

A Sony Pictures employee told Deadline that the company’s systems were “completely paralyzed” while Variety reported that Sony Pictures employees were told to avoid connecting to the company’s corporate network or to check their corporate e-mail accounts.

A company spokesman (SNE) told Deadline: “We are investigating an IT matter.” Sony Pictures did not immediately respond to Fortune‘s request for comment.