What happens if you happen to know your would-be assassin, and in that time that you've found it out they dropped you as their target you kill them?

Another thing as well: I found out who my would-be assassin yesterday was due to the moonmage who located me also thoughtcasted. I confirmed that with the Assassin investigate. However, he apparently abandoned me and I was killed by someone else I wasn't expecting.

Since investigate is a 24 hour timer, would it be possible to know if our would-be assassin dropped us as their target if we were able to correctly investigate originally?