Like we said before, the upcoming movie Changeling is based on a true story: it is based upon the Wineville Chicken Murders.
At the request of Clint Eastwood the reference to this true story has been omitted from from the official synopsis. Clint Eastwood states indeed that 'the important thing […] is whether it’s a good story, and if it’s well told'.
Nonetheless the real names of all the characters have been retained!
From Wikipedia we learn more about the case:
The Wineville Chicken Murders (also known as he Wineville Chicken Coop Murders) took place in the late 1920's in Los Angeles: the crazy Gordon Stewart Northcott kidnapped and murdered boys before being caught and sentenced to be hanged.
(Extract from Jurupa By Kim Jarrell Johnson - Google Book)
Arthur Hutchins, a runaway from Illinois, claimed he was Walter Collins, one of the missing boys, so he could get a free trip to California. LA police, in a hurry to close the case, tried to convince Walter's mother, Christine Collins, that Arthur Hutchins, was her son. When she refused to believe this was her son, she was placed in the psychopathic ward of the Los Angeles County General Hospital for ten days. Only after Arthur Hutchins, admitted he was not Christine Collins' son was Christine released.
About the title of the movie, Changeling:
In some old legend from Europe, a changeling is the offspring of a troll or a faery that has been secretly left in the place of a human child. Either by malice or to use the kidnapped child as servant...
Hence the title of the movie directed by Clint Eastwood.
Nowadays DNA tests would help to avoid such a situation. But other cases where innocents are convicted or secluded still happen unfortunately...