From the Summary: "In 2014 and 2015, reports of Special Weapons and Tactics (SWAT) teams used by law enforcement agencies in allegedly questionable raids or in what appeared to be aggressive responses to public disturbances generated interest among policymakers in federal tactical teams. There is no single source for data on federal tactical teams. The Congressional Research Service (CRS) surveyed federal agencies with law enforcement personnel to collect basic information on any tactical teams they maintain. The number of tactical teams has proliferated among American law enforcement since the first SWAT team was formed by the Los Angeles Police Department in the 1960s. Research has shown that most law enforcement agencies now have a tactical team. Data also show that these teams are being deployed more frequently. As the acronym SWAT implies, such teams are deployed against particularly dangerous criminals and in challenging situations. This report provides baseline data on federal tactical teams."
CRS Report for Congress, R44179