That actually answers a question I was going to ask, which is whether you have a screening process when you hire. You have a code of ethics that creates a formula for looking at new hires.
If you're not going to only rely on people reporting after the fact, do you monitor the workplace at all? Do you have monitoring structures in place so that people can be aware constantly of watching behaviour around them? This would be managers, mostly, who would be in an area where they could watch behaviour. Is there such a monitoring-cum-prevention kind of situation going on? Are you building on that somehow?