U.S. Immigration and Customs Enforcement facilities have varying security levels, with some heavily secured and others more exposed. A gunman in Dallas opened fire on an ICE office from a nearby rooftop on Wednesday, killing one detainee and critically injuring two others. The gunman then took his own life. Former ICE director John Torres says facilities like the one in Dallas have vulnerabilities, such as exposed detainee loading areas. Homeland Security Secretary Kristi Noem has ordered tightened security at ICE facilities nationwide. Observers note that it's challenging to foresee every potential threat.