race riot or politically motivated purge?
In the early morning hours of June 1, 1921, a race riot broke out in Tulsa, where white mobs looted and burned most of Greenwood, the prosperous center of the African-American community in the city. During the 16 hours of rioting, an estimated 300 people were killed(mostly black Republicans), more than 800 people were admitted to local hospitals with injuries, thousands of blacks were left homeless, as 35 city blocks with 1,256 residences were destroyed by fire, and property damage totaled $1.8 million (nearly $17 million as of 2001 after adjustment for inflation). Robertson finally regained control in the city by declaring martial law and sending in the Oklahoma National Guard to police the area and end the chaos. The governor condemned actions by the city and Sheriff's Office and ordered a Grand Jury to investigate, but no one was prosecuted for the deaths, injuries, or damage. An estimated 3,000 blacks fled the city at the time.
Democrats controlled the state at the time.
https://en.wikipedia.org/wiki/James_B._A._Robertson#Governor_of_Oklahoma