The Aphrodite Inheritance 1979 S01E08 (Requested)

Episode: To Touch a Rainbow. David arranges to meet Hellman at the Colosseum after discovering gems in his brother's apartment, little realising that Basileos is stalking him with a rifle. Hellman reveals how his brother came to be in possession of the gems and informs him that he knows who murdered his brother, but tells him he will only reveal the killer's identity in return for the whereabouts of the treasure.