It's not very likely that they have gone back to where they came from.
/// Swedish Liberal MEP Cecilia Wikström told a press conference at the European Commission today that at least 9,000 children were missing from Germany and another thousand from Sweden. ///
/// Ms Wikstrom, Chair of the European Parliament Petitions Committee, admitted that thousands of adult asylum seekers also “go missing” each year once they arrive in
Europe. ///
/// Last year, Germany admitted that it had lost tack of over 130,000 asylum seekers, according to its Government's figures. ///
/// German chancellor Angela Merkel said authorities could not find 13 per cent of the 1.1 million people registered as asylum seekers last year. ///
http://www.express.co.uk/news/world/776009/EU-chief-Cecilia-Wikstr-m-admits-10-000-child-migrant-refugees-missing-in-Europe