While working as a cadet officer in the army, he killed 3 prostitutes and attempted to rape 5 more in the city of Drama in northern Greece from to The surviving victims' testimonies led to his capture on December 13, He was initially court-martialed and sentenced to two life sentences, but it was later reduced to life imprisonment.
In the early days of his imprisonment he was particularly undisciplined and violent but by the late s he turned into an exemplary prisoner. He also had a brother and a sister. The Papachronis family kept a cafeteria in the city where Kyriakos worked since he was little. When he finished high school, he stayed for a while in Athens , making a living from working in various hotels.
In the afternoon of September 9, , Papachronis visited a brothel in the area of Profitis Ilias in Xanthi and requested the services of a year-old prostitute. The coup, however, resulted in a fight, with the woman as claimed by Papachronis underestimated his sexual competence.
He fled furiously to return a few hours later, stabbing the woman to death. On December 20, , while she was looking for customers, Papachronis followed her without her realizing, and stabbed the woman in the back. But her screaming attracted passers-by, and he quickly fled. Ten days later, on December 30, after she had left a screening of a porn movie, a year-old student was attacked by Papachronis.
He stabbed her in the cervix, but was seen by the girl's father, who was waiting for her, and fled. On January 15, , Papachronis attacked a nurse while walking to the train station in Drama. He dragged her under the airbridge and knocked her out, trying to rape her. But he eventually changed his mind and left the woman alive, who was the first victim to give the police a precise and detailed description of Papachronis. He then followed the girl to her house and asked to make love.
