"That... that would make sense. I know I wouldn't be too happy if someone important to me-" Because at the least, she could figure out that L was important to A. "- made friends with the person who killed m-"

Her reasoning caught up and her mouth shut.

Please, she thought, let L just have not mentioned it to him through some brain blip. Happens to the best of us, world-class detectives included, right?