This politico article seems to show the flag (albeit obviously altered, not through photoshop or digital means) as well as another staffer confirming the actual flag was actually found within the room.

Not making an assumption of who altered the flag, but it seems legit.

https://www.politico.com/news/2025/10/15/capitol-police-investigating-swastika-in-gop-congressional-office-00609704