Something similar happened to Gordon Ligbtfoot with Black Day in July.

The song is about the Detroit Race Riots (also known as the 12th Street Rioting) that began on Saturday July 23, 1967. 43 people died in the riots.

The song was released on the album Did She Mention My Name? in January 1968. Martin Luther King, Jr. was shot dead on Thursday, 4 April 1968 and race relations once again became strained.

Gordon Lightfoot interview; https://www.cbc.ca/player/play/1726194667
Gordon Lightfoot