Immigration reform is in the headlines these days, fanning optimism among many undocumented immigrants and their families. Four and a half years ago, however, a much more sober immigration story seized national attention, when a group of teenagers killed the Ecuadorian immigrant Marcelo Lucero in Patchogue, Long Island. They later admitted they attacked him because of his ethnicity.

On a recent evening, 19 Latino immigrants who worked on the clean-up efforts at Ground Zero squeezed into the office of Queens-based psychotherapist Jaime Carcamo. He is a proponent of so-called exposure therapy, when patients describe in detail the memories that haunt them.