Who was the Persian satrap who killed Darius III?

Who was the Persian satrap who killed Darius III? It was Bessus, the satrap of Bactria.

After the Persian defeat at Gaugamela in 331 BC, Darius III retreated eastward while Alexander the Great pursued him. Bessus, a relative of the Achaemenid royal house and governor of the powerful eastern satrapy of Bactria, joined a conspiracy with Nabarzanes and Barsaentes.

The conspirators arrested Darius in 330 BC and tried to use him as a bargaining tool while escaping Alexander. When Alexander’s forces drew near, they stabbed Darius and abandoned him. Ancient accounts differ over each participant’s precise action, so Bessus is best described as the leading conspirator and the principal figure associated with Darius’s killing, rather than necessarily the sole attacker.

Bessus then proclaimed himself king under the name Artaxerxes V and attempted to continue resistance in the eastern provinces. His effort failed: he was captured in 329 BC and delivered to Alexander, who had him executed. Mazaeus and Artabazus were important Persian figures, but neither is the standard answer to this question.