Lewiston’s small population (about 37,000) is why its homicide rates per 100,000 come in multiples of about 2.7 (i.e. 1 homicide per 37,000 is approximately 2.7 homicides per 100,000).
If you look at the 10 years from 2009 to 2018, it looks like there were 9 homicides, which averages out to be 0.9 yearly, or about 2.4 per 100,000 yearly.