The first mention of the name of the Vilnian Special Squad, (Ypatingasis būrys) is on documents dated July 15, 1941. The Special Squad (YB) began as police unit formed after Lithuania was occupied by Germany in 1941. Many were volunteers, particularly recruited from the former paramilitary nationalistic Union of Lithuanian Riflemen (Lietuvos Šaulių Sąjunga) organization. It was composed primarily of Lithuanians, although according to Lithuanian historian Bubnys, a few Russians and a few Poles (or Polish–Lithuanians) served in it too.
This unit was subordinate to German police, and according to Lithuanian historian Bubnys had no autonomy. Amongst the original organizers of the squad were junior lieutenants Jakubka and Butkus. After July 23, 1941, the commanding officer was Juozas Šidlauskas. Squad members were issued Soviet weapons and white armbands and were used as guards and to move Jews from their apartments to the Ghetto. In November 1941, lieutenant Balys Norvaiša, became the commander of the squad and his deputy was lieutenant Balys Lukošius. The size of the squad was reduced to between forty and fifty men. By the end of 1943, Norvaiša and Lukošius were deployed to a self-defence battalion and command of the YB was transferred to sergeant Jonas Tumas. Some of the squad members were wearing uniforms of Lithuanian Army until in 1942 they were issued green SD uniforms with Swastika and skulls on caps. Squad members were also issued SD identity cards. YB was subordinate only to the German Security Police. Longest serving commander of YB was SS man Martin Weiss. Weiss used to not only command executions but to kill victims personally. In 1943 Weiss was replaced by private Fiedler.
YB was created to kill people and killed people during its entire existence time. Most people it killed in 1941. YB killed people in Paneriai, Nemenčinė, Naujoji Vilnia, Varėna, Jašiūnai, Eišiškės, Trakai, Semeliškės, and Švenčionys.
YB also guarded Gestapo headquarters in Vilnius, prison on present day Gediminas Avenue, and Paneriai base. When Germans closed Vilnius' monasteries in 1943, YB guarded facilities until Germans removed nationalised property. In 1943 YB performed far less executions than in 1941–1942. From December 1943 Paneriai was guarded by some SS unit and in 1944, according to Lithuanian historian Bubnys, YB did not perform shootings in Paneriai.
From the August 1943 YB was renamed to a Squad of 11th Battalion of Latvian Legion. Old identity documents were replaced by new documents of Latvian Legion troops. Despite the formal change, YB was still serving German Security Police and SD. In July 1944 YB was moved to Kaunas and stationed at Ninth Fort. There YB guarded prison and before retreating killed 100 prisoners. Then YB was moved to Stutthof, escorted Jews to Toruń, stayed there until in April 1944 received orders to convoy Jews to Bydgoszcz, but members of YB fled from arriving front and Jewish prisoners escaped. Some YB members successfully retreated to Germany, some stayed in the zone occupied by Red Army.
YB killed tens of thousands people, mostly Jews. Ten YB members were sentenced and executed by Soviet authorities in 1945 (Jonas Oželis-Kazlauskas, Juozas Macys, Stasys Ukrinas, Mikas Bogotkevičius, Povilas Vaitulionis, Jonas Dvilainis, Vladas Mandeika, Borisas Baltūsis, Juozas Augustas, Jonas Norkevičius). In total twenty YB members were convicted by Polish and Soviet authorities, four of them in Poland in the 70s. In 1972 Polish authorities arrested three men, one Polish (Jan Borkowski, during the war using a Lithuanized version of his name, Jonas Barkauskas), the other two of mixed Polish–Lithuanian ethnicity (Władysław Butkun aka Vladas Butkunas and Józef Miakisz aka Juozas Mikašius) and sentenced them to death – later commuted to 20 years imprisonment. Other YB members died after the war or live abroad.
In period of 1941–1944, according to the Lithuanian historian, Arūnas Bubnys, citing work of Polish historian Helena Pasierbska, approximately 108 men were YB members. Nonetheless he notes that it is hard two answer two questions: how many members YB had and how many people they killed, and victim number of 100,000 attributed to the organization alone is inflated.