A detainer, also known as an ICE hold, is a request made by ICE to a law enforcement agency to hold an immigrant until an ICE agent is avilable to question the immigrant’s legal status. Although many agencies treat an immigration detainer as a mandatory order of a federal agent, it is only a formal request valid for 48 hours. If your relative or loved one has been detained longer than 48 hours on an ICE hold, you may petition the law enforcement agency for his or her immediate release.