John Mason shot and killed Robert Williams following a disagreement during a craps game on the evening of September 16, 1920. The shooting occurred in an alley off of East Ohio St. on the North Side.

After being shot, Williams ran in to a nearby home, where he died. Mason fled the scene.
Mason was arrested on Wylie Avenue in the Hill District on October 12.

At trial, Mason was convicted of first-degree murder on April 12, 1921, and sentenced to death on October 22, 1921.
No appeal was undertaken. Mason’s clemency petition was rejected and, despite what would appear to be a weak first-degree murder case, he was executed on January 23, 1922. He was buried in the prison cemetery.
As the brevity of the above summary suggests, this case received very little public attention. Much like the Davis case the previous years, a murder among two poor, single Black men who were not from Pittsburgh (Mason was born in Louisiana; Williams lived by himself in a boarding house on East Ohio St., near where he was killed; his death certificate is mostly blank) lacked any of the elements necessary to draw public attention and any of the resources necessary to command the court’s attention.
Pittsburgh Press, October 23, 1921
This simple discussion represents the longest article written about this case and the only article of more than a single paragraph
The struggles of men like Mason and Williams and thousands of other Black migrants were documented by Abraham Epstein, a University of Pittsburgh graduate student in Economics who interviewed hundreds of such men in 1917. His research found high levels of discrimination, wretched living conditions, poor sanitation, and isolation.