Once you have found and chased the thief, the investigator (Chief Inspector) is nowhere to be found. Once you have the key from the curator, you can open the Inspector's house in the Countryside to locate the painting.
You are looking for clues to "The Scream," the stolen painting. The artist on Main Street should have told you that the Chief Inspector bought a painting from him without a frame. Go to the second floor and peel back the edge of the painting there.
go to the far side of counterfeit. on your way, the artist will say something strange about the investigator. continue to her house. use the key you got for the courator. go up to the bedroom and look closely at the painting.
You will not see the investigator anywhere after you finish the security tapes in the museum. However, now that you have the key to her house (in the Country Side), you should find something there.
The locked chest is just a distraction. The painting is on the second floor, disguised by the street artist's abstract work. (Peel back the corner.)
You go up the stairs and peel off the artist's painting. I won't spoil what's under it though...
If you have the key from the Curator, there is only one place to use it. The artist is giving you a clue to where you might find the stolen painting when you enter the Inspector's house in the Country Side.
The Van Gogh painting "Starry Night" is on display at the Museum Fantastique, but also at the Pop Art Museum on Early Poptropica island. One or both are copies, but that does not affect the game play on Counterfeit Island. The artist Vincent van Gogh (1853-1890) is there at the Pop Art museum (probably an actor).
The sidewalk artist told you that the Chief Inspector bought a painting from him. You go to the second floor, where you find a painting slightly peeled back. Click it - it's The Scream (the lights go out and you get noisily attacked).
Go back to Counterfeit Island and use it to open the Inspector's house in the Country Side. On the way, the street artist gives you a clue as to what to look for in the house.
You can draw your own pictures with the artist's canvas in front of the Inn. This has nothing at all to do with the island quest.
You first have to go to the curator on Early Poptropica Island after you receive a package which you have to x-ray. After you talk to the curator, you go back to Counterfeit Island which you go to the old house which is on the far right. But before you can get there the artist which does art similar to Jackson Pollock, tells you that someone bought one of his paintings without a frame which in the house you find the painting which is hiding The Scream.
Finding the Stolen PaintingOnce you get the security guard's timecard (from the Clown Store), the security videos will identify the thief, and you can chase him (with help from the mimes) from the All That Jazz cafe. But he gets away. Fortunately, the package you get from the museum takes you off the island completely, to get the key you need in the Countryside. (Look for the painting by the sidewalk artist when you get in the house.)