Petrakogiorgis' group, named Psiloritis, was active in the regions of Mt. Ida, Mesara Plain, Mt. Kedros and Amari, and was often engaged in close combat with the occupation forces. He and his men fought in fierce battles in the region, such that at Papa to Perama (Παπά το Πέραμα), Kouroupitos (Κουρουπητός), Koutsounares (Κουτσουνάρες), Poros Stavrou (Πόρος Σταυρού), Trahili (Τραχήλι) and Madari (Μαδαρή). They also conducted several sabotage operations, smuggled men and equipment, and participated in the abduction of General Heinrich Kreipe. These activities allowed Petrakogiorgis to demonstrate his leadership and military skills, earning himself the nickname the eagle of Psiloritis. Yet, they also provoked German reprisals which involved the execution of civilians, the confiscation of Petrakogiorgis' personal property and the destruction of villages (Magarikari, Kamares, Lochria), with the worse being that of Vorizia () which was flattened after heavy aerial bombardment by Stuka dive bombers.