BLOOMINGTON, Ind. — Justin Williams was baking a tray of gluten-free seeded bread for the next morning’s farmers’ market when his phone buzzed. It was a friend who grows organic sprouts, nervously wondering if he should bring along a shotgun to market.

It has been a summer of fear, protest and tension in this crunchy college town ever since the popular Saturday morning farmers’ market was jolted by allegations that a husband and wife who had been longtime sellers of organic tomatoes and kale were also white nationalists.

The accusations exploded into public view after activists and online sleuths used federal court records and the leaked archives of a far-right message board to uncover a digital trail they say connects the couple who own Schooner Creek Farm to an organization that promotes white nationalism and “white American identity.”

The rumors of white supremacy amid the stalls of clover honey and sweet corn left farmers and shoppers reeling: Not even their seemingly placid farmers’ market was immune from the battles over extremism convulsing the country at a time of rising alarm over white supremacist violence.