Talk to your lawyer. And fire him anyway, there is no reason to keep a person like this in your team, it will get worst. Then send a short and non-inflammatory

Talk to your lawyer. And fire him anyway, there is no reason to keep a person like this in your team, it will get worst. Then send a short and non-inflammatory message to the rest of the company so everybody will know you won't tolerate this kind of behavior and act swiftly on it.