What are the keys for?

1. Keys are earned during limited-time events, called Detectives Needed Challenges. When a challenge is active, you will see a stopwatch icon on the left side of your island scene. If you click on the icon, you will see the prizes, how many keys are needed, your progress, and whether cases are earned from playing scenes or competing Help Wanted cases or both. 2. Some decoration from past collections set will return, but not all. Past grand prizes will not return. Marvelous prizes from pink star boxes often return as Detectives Needed Challenge Prizes. Some return as items that can be purchased with diamonds or real money.