Federal agents shot and killed 37-year-old Alex Pretti in Minneapolis, the second such killing in the city within less than three weeks. Pretti was an intensive care nurse with no criminal record, yet federal agents raced to portray him as a violent ‘gunman’ who threatened to ‘massacre’ law enforcement. Video evidence directly contradicts this account. Since then, protests have erupted in the US. The Trump administration said it was ‘reviewing’ the incident. Lucy Hough speaks to the Guardian columnist Moira Donegan