I partly disagree. I fully agree with the notion that if he killed 10 people that we know of, there's more than likely others. Whether it was many others or just a few others is debatable. We do know that those murders were tied to the DeMeo crew, and the Gemini Twins were part of the DeMeo crew and the Gemini Twins were probably the main hitters for the DeMeo crew, so yeah he was more than likely a participant in most if not all of them. He might as well be as far as I'm concerned. There's actually a full list somewhere detailing exactly who, when, where, and why they were killed.