Father and son were about to open their pizza parlor when they noticed a boy next to their shatter, stabbed several times to death. The victim had no wallet with him so he's classified as a John Doe. The place is frequented till late night by drunk young guys so it's not easy to identify who the murdered really is. Anyway a call made by his mobile phone the next morning lead the detectives to a local drug dealer (and fence): he's just a thief and not a murder, but he allowed detectives to locate the victim's clothes, stained with cow blood. The owner of a local slaughterhouse had knives the same size of the murder weapon and he used to be harassed by the victim, an activist against animal butchering. What seemed to be an argument went bad actually hide something more important related to meat market and the corporation in charge of trading the meat. An agreement settled in the past and end up under the rug could be called into question.
It's essential to guarantee food quality, but it's not easy for common people to deal with powerful corporation. When it all become of public domain, like in a trial, people affected are willing to come up and testify.