James Murry, who plans to run as an independent against Sheriff Gerald Robinson, made the accusations.
He accuses Robinson of shutting down his office last month so staff and deputies could come and work at their boss's fundraising event.
Murry also claims Robinson threatened to deal with anyone who supports his opponent, particularly Murry.
"I find it difficult to be the sheriff and instead of enforcing the law, you're breaking the law and you're requesting the citizens to abide by the law," Murry said.
Sheriff Robinson would not address the complaints. His attorney is expected to address the accusations in a response to the Arkansas Ethics Commission.