The small village of Kasčiūnai in the forest, on the high bank of the river Merkys, was a partisan stronghold and refuge throughout that turbulent period, reliably protecting and patronizing the heralds of freedom. When it was not possible to improve radio communication, the partisan commander Kazimieraitis and some of the staff members left the winter headquarters and from 1946-01-04 to the end of March stayed at the Adolfas Ramanauskas-Vanagas command post in Kasčiūnai village, at the homestead of Juozas Jakavonis-Tigras' parents.

The bunker was dug by the partisans in 1945 next to the barn, where an entrance and a several-meter tunnel to the bunker were made. In this bunker, the attack on Merkinė was planned, the rules for awarding distinguished partisans were prepared, the Lithuanian resistance newspaper "Laisvės varpas" was printed. Here Vanagas described the hours he had experienced, what a person feels when he is on the verge of death, when he clearly heard the Chekists furiously hammering steel rods around the bunker and digging the ground in the barn. About 60 soldiers turned everything over in the homestead while looking for them. During that time, he wrote down a full school notebook.

The bunker was not discovered, but more people knew about its existence and it became unsafe to stay in it. Therefore, in the spring of 1946, it was destroyed by the partisans themselves and the command post was moved to the summer bunker. According to J. Jakavonis, the hole for the bunker was dug by commander A. Ramanauskas-Vanagas, his adjutant Vincas Ivanauskas-Gegutis, Albertas Perminas-Jūrininkas, Bronius Čaplikas-Strazdas and Juozas Jakavonis-Tigras.