Layla became even more upset after that.

Elliot was not at all surprised.

Everything would make sense if Layla was the one who took the box; it explained why they couldn't seem to find out who stole the box because no one would suspect a four-year-old child.

Layla was very dependent at the time, and who would suspect a child who couldn't take care of herself?

Apart from that, it also explained why the content inside the box was never publicized or used to blackmail Elliot after it was taken.