A police sergeant in Virginia who was assigned to monitor the protests related to Gov. Ralph Northam was suspended Wednesday after being identified by an anti-fascist group as having an “affinity with white nationalist groups.”

The sergeant, Robert A. Stamm, 36, “has been placed on paid administrative leave pending the results of a review,” the Virginia Division of Capitol Police said in a statement. Sergeant Stamm joined the division in 2014 and was promoted to his current rank last year, officials said.

“There is a review policy in place, and we will follow that policy,” Col. Anthony S. Pike, the division’s chief, said in the statement.

Reached by telephone on Wednesday night, Sergeant Stamm declined to comment.

The authorities said in the statement that they were “made aware” early Wednesday morning of a “possible violation of division policy” by Sergeant Stamm. A police official specified that the possible violation that prompted the suspension was outlined in a blog post published on Tuesday by Antifascist of the Seven Hills. The group describes itself as an organization that seeks “to fight fascists” in Richmond, Va., “as communists and anarchists united in militant opposition.”

In the blog post, the group published several pictures — apparently pulled from Sergeant Stamm’s social media accounts — of what it said was him with tattoos, flags and banners that it said were symbols and images associated with Nazis and white supremacists.