At the end of 1943 he was named ground liaison officer with the German XV Army Corps.

Tomašević was also a commissionaire of the GRAVSIGUR, the Croatian security police, for districts of Modruš, Vinodol-Podgorje, Lika-Gacka, Krbava-Psat, Bribir and Sana-Luka.

[1] During the Lorković-Vokić plot, Tomašević offered his help to the Allies if they invade the Dalmatian coast in August 1944.

He was tried in front of the Military Council of the Court Martial in Belgrade and sentenced to death on 19 September 1945.

[1] Tomašević is also remembered for his career during World War I, as he was a commander of a company in which Josip Broz Tito, the future authoritarian President of Yugoslavia, served as a sergeant.