Whoever is responsible for trying to manipulate the U.S. midterm elections must face significant new sanctions.

Facebook’s announcement on Tuesday that it has detected and deleted “eight Pages and 17 profiles on Facebook, as well as seven Instagram accounts,” should serve as a wake-up call. Facebook says the deleted activity violated its “ban on coordinated inauthentic behavior.” But while Facebook doesn’t yet know which actor is responsible for the posts, it has clarified that the responsible party took significant steps to hide their tracks. Facebook also notes that it has shared its findings with the FBI.