david steveson is following the story with more on what happened. >> reporter: i'm standing at hayes dairy farm, it opened in january onramps that are part of the now demolished central freeway. these urban farms included three beehives. the hives you are seeing now were poisoned by someone this week and police are now investigating. >> the colony became a gas chamber. and all the bees died. >> reporter: san francisco beekeeper karen petteross is now conducting an autopsy on her bee colonies. someone entered hayes valley farms and sprayed pesticides inside the ventilation of three hives. >> i understand that there is one person in the neighborhood and only one who has expressed any negative sentiments about honey bees being on the property. >> they increase the fertility by pollinating, so we have more fruit, more abundance. but they also provide honey for us. >> reporter: sales proceeds from the upcoming honey harvest were set to help fund the project. farm managers are talking now about garden new colonies with security cameras or motion detectors. the killings here come after a re