JUST OUTSIDE THE MAIN DOWNTOWN part of Athens lies Kolonos, an old Athenian neighborhood near the archaeological park of Akadimia Platonos, where Plato used to teach. Along the maze of narrow streets, flower-filled balconies hang above open-air markets, and locals gather for hours at lazy sidewalk cafes, sipping demitasse cups of espresso and downing shots of Ouzo in quick gulps…

It was a neighborhood Costas Tsalikidis knew well. He lived at No. 18 Euclid Street, a loft apartment just down the hall from his parents. Slim and dark-haired, with a strong chin and a sly smile, he was born in Athens 38 years earlier to a middle-class family in the construction business. Talented in math and physics from an early age, he earned a degree in electrical engineering from the National Technical University of Athens, considered the most prestigious college in Greece, where he specialized in telecommunications, and later obtained his master’s in computer science in England. Putting his skills to good use, for the last 11 years he had worked for Vodafone-Panafon, also known as Vodafone Greece, the country’s largest cell phone company, and was promoted in 2001 to network-planning manager at the company’s headquarters in the trendy Halandri section of Athens.

On March 9, 2005, Costas’ brother, Panagiotis, dropped by the apartment. He thought he’d have a coffee before a business meeting scheduled for that morning. But as he entered the building, he found his mother, Georgia, running up and down the corridor yelling for help.

“Cut him down!” she was saying. “Cut him down!”