After you get the picture of the thief, you talk to the mimes. They act a singing duet, trying to tell you to go to the jazz club. Afteryou talk to the thief you go through a mini-scooter chase after him. Then he gets away.
The art thief is back on Counterfeit Island. As part of Counterfeit island, you don't need to do anything in Early Poptropica except get the key from the curator at the Pop Art Museum, then return to Counterfeit Island to open the Inspector's house.
As it turns out, it's impossible to. You are used by the thief to cover his theft. You will eventually find and recover it.
After you chase the thief on the scooters, you will get the key to the cottage in the Country Side from Early Poptropica island. There you will find the missing painting and enter the lair of the Black Widow.
Night
The one that is right there Downtown. Show the photo to the mimes for the clue first.
You don't find him. He has made a clean getaway. Go back to the museum and get the package from the assistant curator.
To win on Counterfeit Island, you must take the Underground Tour, collect the pieces of the torn pictures, get a job at the museum, find the thief, and recover the stolen artwork. [ For the solution(s) see the related questions.]
After you chase the thief, you get a package and go to Early Poptropica island. There you get a key that opens the Inspector's cottage. You find the stolen painting and the lights go out.
Go back the museum : you have a package waiting for you.
She warns you that there is a notorious thief at work on Counterfeit Island, and gives you the key to the Inspector's house in the Country Side.
The mysterious man on Counterfeit Island is the art thief's henchman. Later on in the mission you two work together to stop the real art thief. Hope this helps!
She is nowhere to be found. However, if you return to the museum after chasing the thief, you may get another clue.