The unit was established on 7 September 1990. It initially comprised 225 volunteers, many of whom had been enrolled in the First Croatian Police Officer course (), which was formed in order to create a police force loyal to the new Croatian government during the political tensions leading to Croatia's proclamation of independence from Yugoslavia, and the subsequent escalation of the Croatian War of Independence. It was the first Croatian fighting unit taking part in the war. It was also the only fighting unit of Croatian Special Police Forces at that time, and the first unit of the future Croatian Special Police. Its first missions were to restore public order in areas where Serbs participating in the Log Revolution were trying to wrest control from the authorities; to take control of the barracks and confiscate weapons of the Yugoslav People's Army, whose authority in Croatia was rescinded by the country's government after it sided with the Log Revolution; and to train units which would later be organised into the Croatian Armed Forces. The unit saw its first military skirmish on 1 March 1991, the Pakrac clash. It took part in many battles during the war, including the Plitvice Lakes incident, battles of Glina, Topusko, Petrinja, Nuštar, the Siege of Dubrovnik, and Operations Maslenica, Medak Pocket, Flash and Storm. Members of Lučko ATU chain of command, including General Mladen Markač were tried by the International Criminal Tribunal for the former Yugoslavia (ICTY) for alleged war crimes committed during Operation Storm. They were acquitted of all charges on appeal.