B-kun had just finished speaking to Violet. In his mind he says 'She liked to cook too...' Now she could refer to Violet that isn't a real stretch, but the word liked is what causes to me to rethink this. If he had thought 'She likes to cook too..' then Violet would most likely be the killer he was thinking of, but liked...this causes me to think it may be an old acquaintance, ex wife or someone else from their past.