The documentary uses several cases , from the 1964 murder of Kitty Genovese , when 38 neighbors in Queens heard or saw parts of the fatal attack and did nothing , to a 2005 hazing ritual that killed Matthew Carrington , a 21-year-old student at California State University , Chico , to make a point about herd mentality : that people who might give help when by themselves will , among others , hold back and follow the cues of a majority .