On May 22, 1970, responding to a bogus emergency call to help a pregnant woman, St. Paul patrolman James Sackett was killed by a sniper's bullet fired from a high-powered rifle.

The white officer's assassination was the most shocking event in an era of shocking, racially charged events, punctuated by bombings at Dayton's Department Store and elsewhere, police harassment and shootings of young black men, an alleged hijacking plot, and random acts of urban violence. a once peaceful, close-knit community, St. Paul's summit-university neighborhood had reached a boiling point, heated by...