Confidence tricksters are targeting international postdocs and students in the United States, according to complaints passed on to the National Postdoctoral Association (NPA) in Washington DC. Telephone callers claiming to be from US Citizenship and Immigration Services (USCIS) tell trainees that they have improperly completed a form, and that they face a fine or deportation. This is not agency procedure, says the NPA. Callers know the target's name, date of birth, address, phone number and case number. People who suspect that they have been targeted should report the scam at go.nature.com/poexjx. The USCIS did not respond to requests for comment.