What do we know?
The intern is the only person who we know has handled this box alone.
The pig’s heart in the box is a practical joke by the intern to try to lighten the mood.
Means: He’s in hiding
Motive: Viral marketing
Opportunity: Clearly, he could kidnap himself at anytime
Means: Access to hired hitmen and/or pinking shears
Motive: Jealousy. Wants to be the #1 designer
Opportunity: Works close enough with Fabuleux that he had plenty of opportunity
Means: Pushed Fabuleux off the yacht. The heart in the box is a fake.
Motive: Is related to designer of rival fashion house. Just trying to help the family
Opportunity: Well he/she’s an intern. They can get anywhere and no one ever notices them
Means: Pushed him off the yacht. Pinking shears. Hitmen.
Motive: Jilted lover. Fabuleux has never responded to her sexual advances, because she’s the wrong gender.
Opportunity: No one has more access to Fabuleux than his “trusted assistant”
My bet is on Lindra. Sex (or lack of here) is always the root cause in these things.