AI keeps attacking dead actor

I have an AI that keeps pursuing the character until they fight back and kill them or the AI kills them. When the AI kills the character, they die and are destroyed but the AI continues on as if the character is still alive. The destroyed actor’s object reference is changed to “None” in the enemy AI’s Behavior Tree but the “bIsSeen” is still true. I tried casting to the actor responsible for the AI’s stimulus to check whether it’s dead or not but that didn’t work. How can I get my AI “bIsSeen” bool to set to FALSE?