US Secret Service and local police apprehended a suspect at a Donald Trump campaign rally on Saturday after someone in the crowd shouted “gun” but no weapon was found.
In a statement, the federal agency said an investigation was continuing, but US media in Reno reported that the Reno Police Department had released the suspect.
Mr Trump was bundled off stage by security officers after an apparently false gun scare during a campaign appearance.
US media cited law enforcement sources reporting that no gun had been found after a cry of alarm in the crowd, and Trump swiftly resumed his speech in Reno, Nevada.
The 70-year-old Republican tycoon reappeared just minutes after being led away by three Secret Service officers, who shielded his body with their own.
Minutes later, he reappeared to cheers, declaring: “Nobody said it was going to be easy for us, but we will never be stopped, never ever be stopped.
“I want to thank the Secret Service. These guys are fantastic. They don’t get enough credit. They don’t get enough credit. They are amazing people.”