On the morning of July 4, an American marketing professor was walking towards his ex-wife’s house in Athens to pick up their two young children. It should have been an unremarkable, if strained visit – the couple had apparently been disputing the terms of custody arrangements.

Greek officials say the broad-daylight attack came one day after a custody hearing over the victim's 10-year-old twins.

Greek police have arrested at least five people in connection with the killing of a UC Berkeley professor, including the professor’s ex-wife, according to CNN and local news reports.