SPECIAL POLICE UNITS

Special Police does not have a consistent international meaning. In many cases it will describe a police force or a unit within a police force whose duties and responsibilities are significantly different from other forces in the same country or significantly different from other police in the same force as described in the following sections. The status of Special constable in many (if not most) cases does not indicate a member of a special police force; in countries in the Common wealth of Nations and often elsewhere it will usually describe a voluntary or part-time member of a national or local police 

force or a person involved in law enforcement who is not a police officer but has some of the powers of a police officer. Commons they are handle big crime using weapon and explosive .they also expert  on tactis,weapon .almost every country have special unit  also we call counter terrorism unit or SWAT(special weapon and tactics team ) for example US(SWAT),Germany(GSG9),ENGLAND(SAS),France(GIGN),Indonesia(GEGANA),etc.