I knew about it due to Idol's shoot interview that came out a few years ago, I think via Highspots.
In Gary Hart's book, he had some disturbing things to say about Idol during Idol's earlier years......This was back when Idol had the heavier powerlifter look with dark hair, nothing like the persona he crafted later in his career. They were both touring Australia and Hart's apartment was directly underneath Idol's. He said Idol bought a pitbull and was abusive to it whenever it would act up or not do what he'd say. Hart said one day he saw Idol holding the dog over the balcony by its leash/neck (Essentially hanging the damn dog). Then on another day, the pitbull finally attacked back and chewed up Idol's legs.
Weird stuff, and not something I'd expect out of Idol. Not that we truly know what type of person he is. Hopefully he grew out of that odd, abusive-to-animals/dogs mentality later in life.