Police SWAT teams (Special Weapons and Tactics) are a special force involved in law enforcement, riot control and possibily violent operations. Every country has a special force comparable to the SWAT, usually under a paramilitary internal organization.
Compatible Lego SWAT are ones of the children's favourite toy as playing police operations is generally among the more interesting activities for kids. We have Tanks, the Police SWAT Station, Command Trucks, Armored Cars and SUV's, Hovercraft and many more.
SWAT are mostly deployed to enforce search warrants and narcotics, but they also operate in case of terrorism and crowd control.
They were created in 1964 in Philadelphia to overcome an escalation of bank robberies. The results were so satisfying that the SWAT's were adopted by all other US police departments, starting from the Los Angeles police.
You cannot buy original Lego SWAT Sets at the official shop because Lego has a policy of not producing this sort of playsets. There are no Lego war and army related themes, so you cannot find any Lego SWAT on the shelves. But there are many more companies producing Lego compatible bricks toys.
SWAT's are also known for the 1970's-80's war on drugs where hundreds of raid where deployed to fight the local drug lords. In 1980's the raid numbers increased to 3000 each year, and by 1996 they got to 30.000 annually.