I saw Peter killed.

Hi,

I think I'm very likely to encounter and need to express one of the three types of situations without mentioning the doer involved:
1. I saw something in a state.
2. I saw something was being done.
3. I saw the whole act.

For instance, Peter was killed and I saw it.
1. I saw Peter killed. I saw Peter was killed. I saw Peter after he was killed. I saw Peter dead. Which one describes that I saw the state?
2. I saw Peter being killed. (It means I saw Peter was being killed)
3. I saw Peter while he was killed. Does this sentence describe I saw the whole act?

Thank you very much.