A video circulating on social media appears to show US Christian author Eric Metaxas punching someone in the face and then running away.
The incident took place earlier this week when crowds were leaving Donald Trump's acceptance speech at the Republican National Convention in Washington DC.
The video shows a man riding a bike and repeatedly yelling expletives about the US president. Then a man appearing to be Metaxas punched the protester in the face. Immediately a woman, who is thought to be his wife, is heard shouting: "Eric!"
The man that was hit confronted Metazas saying: "You just attacked me bro, that's a felony."
Metaxas then starts running backwards as the man continues to confront him. The protester is then intercepted by the Secret Service. It's been reported that the video of the incident was shown to the Secret Service and the protester was let go.
The protester has been identified as Anthony Paul Harrington from Portland, Oregon.
Metaxas hasn't spoken about the incident and no charges have been filed. However, his long-time friend and senior editor at The American Conservative Rod Dreher has defended his move.
He wrote in a blog: "If Eric felt that the screaming cyclist was a threat to his party - which you could easily imagine if the guy was headed towards them - then that could explain why he reacted as he did. If that's what happened, it doesn't necessarily make it right, but it does make it understandable. My guess is that something like that happened, because I cannot emphasize strongly enough how out of character it is for Eric Metaxas to be violent in any way."
Metaxas is a conservative radio host and is known for his biographies on William Wilberforce and Dietrich Bonhoeffer. He has also written scripts for Christian children's TV show VeggieTales.