After you identify the painting thief from the security videos, and find him Downtown, you will chase him on the scooters. After this, you get a package at the museum that will take you to Early Poptropica Island, where you will get the key that fits the cottage door.
On The Country Side Of Counterfeit Island
just click the top right corner
go to the paint splotched painting and click in the upper left hand corner
I forget but I think the lady in the museum gives the key to you...
If you mean on Counterfeit Island, the inspector's house is all the way to the left. Keep going left until you reach a large house.
go to the second floor and tear the painting
You get the key late in the game, after the activities of the first night. You do not have to look for it.
It is in the Inspector's house in the Countryside. There is no way to enter the house. You will be given the key to it later in the game.
The Inspectors house is on the far right of the island. In the countryside. You can't get in until you obtain the key from the creator.
The key card does not open any house. You use it much later to enter the underground treasure trove of the black widow.
you have to go to early poptropica in the museum . click on her then choose the last question, listen, then she'll give you the key for the inspectors house on the county side. use the key then go in
You only pass there once, taking a green balloon to the crying French boy. When you get the key from Early Poptropica, you can enter.