I have tried a direct approach.

I've worked with an guy who had served time for manslaughter who threatened to kill me within earshot of our coworkers.

My workplace did some conflict resolution and we worked it out. We sort of still disliked each other but there was an element of respect and camaraderie because we had to rely on each other. We worked well together.

One time years later I was helping someone get their car out of a snowbank and another person stopped to help. We were both kinda bundled up and talking to each other. After we pushed the car out we looked at each other and pulled our collars down/took off our toques at the same time in recognition. I was oddly happy to see my former almost murderer.