Some scholars focus on the organization of "crimmigration" as it relates to the mass removal of certain immigrants. Jennifer Chacón finds that immigration law enforcement is being decentralized. Customs and Border Patrol (CBP), Immigration and Customs Enforcement (ICE), and the Department of Homeland Security (DHS) are the central law enforcement agencies in control of enforcing immigration law. However, other federal, state and local law enforcement agencies, such as sheriff's offices, municipal police departments, the Federal Bureau of Investigation (FBI), and the Drug and Enforcement Agency (DEA), aid in immigrant removal. In 1996, Congress expanded power to state and local law enforcement agencies to enforce federal immigration law. These agencies keep people locked up in jails or prison when they receive an "immigration detainer" from ICE, and therefore aid in interior enforcement. In addition, some agencies participate in the State Criminal Alien Assistance Program ("SCAAP"), which gives these agencies financial incentives to cooperate with ICE in identifying immigrants in their custody.