PHILADELPHIA—On Thursday evening, surrounded by a throng of reporters with cameras and soggy from the light rain, Joey Johnson performed the same trick he’s been performing for three decades. From a few rows back, it was briefly possible to see the flame that was licking the American flag he held in his hand, but the fire went out after just a moment or two.

CLEVELAND — Longtime free-speech activistGregory “Joey” Johnson, who took his fight for the right to burn flags all the way to the Supreme Court, was arrested and charged with disorderly conduct following a flag burning outside the Republican National Convention on Wednesday. Police said he accidentally set himself on fire, prompting them to take action to extinguish the fire and disperse the crowd, but eyewitness accounts as well as photo and video evidence seem show a different story.