A random paper on crime and policing from 2017 covering two months in one city that shows a small difference in some types of crimes (complaints of felony ass

A random paper on crime and policing from 2017 covering two months in one city that shows a small difference in some types of crimes (complaints of felony assault, burglary, grand larceny) but not others (murder, rape, robbery, grand theft auto) and it's on Hacker News? How? Looking at the graph of the period after this slowdown, the crime also appears to be down year-over-year by about the same amount as during the slowdown.