Raiet was a low-level Jhereg operative who committed the cardinal sin of the organization: he agreed to testify to the Empire against his fellow criminals.
For one of his first assassinations, Vlad was hired to do away with Raiet permanently. Vlad paid off Raiet's mistress, Treffa, to trick the three Dragonlords who were guarding him, using a silence spell for "privacy." By the time the Dragonlord guards got suspicious and broke down the door, Raiet's soul had been destroyed, Morganti-style. Vlad was long gone, and Treffa had changed her name and moved far, far away.