The letter continued: “This violence was the only violence that occurred during this protest, and it was directly attributable to the negligent actions of one of your officers. ... That it could have been avoided is problematic; that it could have triggered escalated violence is inexcusable.”

Richmond police spokesman Gene Lepley said Wednesday that Durham “is responding to the letter in private, not in public.”

A second letter, dated Wednesday, detailed concerns related to Monday’s protest, in which 13 people were arrested after blocking southbound I-95 near Belvidere Street during Monday evening’s rush hour.

The ACLU didn’t criticize the arrests — protesters were taken into custody by Virginia State Police, not the city department — but rather how Richmond officers told people standing on public sidewalks that they had to keep moving. There was a similar complaint lodged in the earlier correspondence.

“Members of the public have a right to stand on public sidewalks without moving, especially where there is no objective evidence that their doing so is obstructing the police in any way,” the second letter said.

The letters asked for a meeting with Durham to discuss the ACLU’s concerns and urged immediate and decisive action.