An “art lover” builder has confessed to stealing three priceless artworks in an audacious theft from the National Gallery in Athens nearly a decade ago. This week police recovered the works by Pablo Picasso (1881-1973) and Piet Mondrian (1872-1944) wrapped in plastic sheets in a gorge south-east of Athens.

Taking just seven minutes, the incident occurred at the height of Greece’s economic crisis in 2012 and has since been dubbed the “theft of the century”. Police initially believed two experienced burglars manipulated the alarm system to send the only guard on duty in the opposite direction of their escape route – through a balcony door. Later a condemning inquiry discovered that the museum had not updated its alarm system for more than a decade, while some galleries were out of range of CCTV.

Several artworks were stripped from their frames, including Picasso’s ‘Head of a Woman’ painted between 1934 and 1939. Picasso personally gifted the cubist painting to the nation in 1949 for their resistance against fascist and Nazi forces. He inscribed on the back of the canvas: “for the Greek people, a tribute.” According to Greece’s culture minister, Lina Mendoni, this inscription would have made it “impossible to sell or go on display“. Also snatched was a sketch by Italian artist Guglielmo Caccia (1568-1625), known as Moncalvo, and ‘Stammer mill’ by Dutch painter Mondrian. Another Mondrian painting was dropped during the escape.

Authorities were shocked to learn the ‘brazen thieves’ were in fact a lone 49-year-old construction worker called George Sarmatzopoulos. “I made constant visits to the National Gallery and became acquainted with the works and the space until I believed that one of them could become mine,” he confessed to police. “These thoughts tormented me for about two years and led me to make the biggest mistake of my life.”

On the day of the burglary Sarmatzopoulos wore all-black clothing, carrying with him a bag of construction tools. A beeping sound alerted the guard when he entered through the balcony door, but it stopped as soon as the door was closed again. “That’s when I decided that annoying the security guard was the best way to carry out the theft, by making him believe that there was a technical problem in the alarm zones,” he said. Immediately after the heist, he noticed a cut to his hand and used the Moncalvo drawing to wipe away the blood.

“I am deeply regretful. I declare my complete remorse,” claimed Sarmatzopoulos during the interrogation. Sarmatzopoulos hid the other masterpieces in his home for years, only later moving them to a warehouse and then recently to the gorge. Mendoni described the discovery as “a special day, [a day of] great joy and emotion.” Michalis Chrisohoidis, citizens’ protection minister of Greece, added it “took a Greek to deprive” the nation of the masterpieces and “Greeks to bring it back”.