The Case of the Mysterious Mug's Absence

Our team is in disarray. The office coffee mug that was once the pride of our team has gone missing. Last seen in the break room, it vanished without a trace. We have reason to believe it was taken by the notorious "Mug Thief" who has been known to strike at any moment.

Here are our clues:

What do you think happened to the mug?

The Mug Thief's Last Known Whereabouts Sugar Packet Red Flags Whiteboard Cryptic Message

Solutions:

Suggest your theories in the comments below: