Many of the rumors of rigged votes have taken on a life of their own on social media, where conspiracy theories flourish and accusations fly. The reports have left election officials and the local authorities scrambling to verify claims of mischief and, often, to offer reality checks.

One of the most fiercely contested battlegrounds, Ohio, has been a hotbed of suspicion. Over the weekend, a political activist with more than 30,000 Twitter followers wrote a post claiming that Trump supporters with dogs were threatening black voters who went to the polls early in Cincinnati. The post sent his followers into a frenzy, but local officials said the man, Jim Wallis, was making a false claim. The message was later deleted.

“I saw a couple of Seeing Eye dogs, one miniature horse wearing a campaign sign and another rather large but friendly dog on a leash,” Tim Burke, the chairman of the Hamilton County Board of Elections, told The Cincinnati Enquirer.

In Butler County, Ohio, Leah Edwards notified the authorities about voter fraud when she saw a man taking notes and photographing gravestones at a cemetery. “I can’t think of any other reason a person would be doing this,” she wrote on the Facebook page of the Butler County Sheriff’s Office.