Responses
I mean a brainwashed and manipulated kid would totally believe that since she would actually think FL might have ordered a knight to do the killing. In our perspective, we know the truth, but since Lilia is so blinded with grief, revenge, got brainwashed and manipulated, of course she wouldn't believe anything good about FL and straight out focusing on her revenge
A three year old can drown an adult in panic. So it's not impossible, especially if the victim is hit so hard while they don't suspect anything that they can't defend themselves.
Lilia might just have no brain at all because how tf do you just believe that a kid the same age as you killed your OLDER brother??