Police in Greece are searching for the killer of a University of California Berkeley professor who was shot and killed on July 4 while visiting Athens to see his children and attend a family custody hearing.

The ex-wife of a University of California, Berkeley professor who was fatally shot during a visit to Greece earlier this month is among five people who have been charged in his killing, reports say.

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.