How to find out if someone is detained by immigration. Feb 12, 2025 ยท If you are searching for someone who may have crossed into the United States, U. The A-Number must be exactly nine digits long. Immigration and Customs Enforcement (ICE). If you know the detainee's A-Number, ICE recommends you use the A-Number search. In this guide, we will explore the best way to locate someone in ICE detention and other tips to assist them. Immigration and Customs Enforcement website allows you to search by name or A-Number for anyone currently in ICE custody, or currently in CBP custody for 48 hours or more. If the A-Number has fewer than nine digits, please add zeros at the beginning. This guide will help you understand the process of locating a detainee and what to do next. Customs and Border Protection (CBP), there are steps you can take to find out where they are being held and how to contact them. What is Immigration Detention? If someone you know has been taken into custody by Immigration and Customs Enforcement (ICE) or U.