San Francisco’s Department of Building Inspection said on Tuesday it was investigating a complaint that Twitter had created makeshift bedrooms at its headquarters in the city, as new owner Elon Musk seeks to instil a “hardcore” culture at the social media company.

“We need to make sure the building is being used as intended,” Patrick Hannan, a spokesman for the department, said in an email. “There are different building code requirements for residential buildings, including those being used for short-term stays. These codes make sure people are using spaces safely.”

“No one is above the law,” he said.

The complaint - sent on Twitter to San Francisco’s 311 service - came after Forbes reported that multiple rooms in Twitter’s office were being converted into sleeping spaces, describing them as “modest bedrooms featuring unmade mattresses, drab curtains and giant conference-room telepresence monitors.”

Musk appeared to confirm the report, writing on Twitter: “So city of SF attacks companies providing beds for tired employees instead of making sure kids are safe from fentanyl. Where are your priorities @LondonBreed!?” He tagged San Francisco Mayor London Breed, whose office did not respond to a request for comment.

Twitter, which gutted its communications team in a round of mass layoffs after Musk took the helm, did not respond to a request for comment.

The apparent installation of bedrooms at Twitter’s headquarters comes after a product manager at the company shared a photo of her sleeping on the floor of what appeared to be a meeting room. “When your team is pushing round-the-clock to make deadlines sometimes you #SleepWhereYouWork,” she said in reference to the photo of her wrapped in a sleeping bag.