They were among the nation’s top priorities for deportation, criminals who were supposed to be sent back to their home countries. But instead they were released, one by one, in secret across the United States. Federal officials said that many of the criminals posed little threat to the public, but did little to verify whether that was true. It wasn’t. A Globe review of 323 criminals released in New England from 2008 to 2012 found that as many as 30 percent committed new offenses, including rape, attempted murder, and child molestation — a rate that is markedly higher than Immigration...