Kostas was arrested on December 4, 2010 in Nea Smirni case (possession of weapons and explosives). In January 2014 released on bail and went on the run. In December 2014, he was sentenced in absentia to 16 years. He was then rearrested with Marios Seisidis in August 2016 and sentenced to 2 years and 9 months for using forged documents and car registration plates, car theft and disobedience to authorities.
On June 13, 2019, he was arrested with two other comrades in Thessaloniki, during expropriating a guarded money transport that was about to refill an ATM at the university hospital AHEPA. They were caught by cops of the counter-terrorism unit just when they were getting in their car to leave from the spot. The two comrades are Giannis Dimitrakis and Dimitra Syrianou. There have been searches in their houses and many personal things have been taken. Media created a wave of terror.