A man was arrested outside the Karen Read trial on the opening day of the high-profile retrial after State Police troopers reportedly told him several times to leave the buffer zone.

Arlington man Bao Nguyen, 42, is accused of lingering and filming within the buffer zone outside Norfolk Superior Courthouse in Dedham.

A buffer zone has been established outside the courthouse during the Read proceedings, as protesters descend upon the area.

State Police troopers on Tuesday morning reportedly asked Nguyen to leave the buffer zone, and explained the “protocols and rationale of the Court.”

When he didn’t exit the zone after several requests, troopers arrested him for violating the order.

Once in custody, Nguyen asked for medical attention, and he was checked out by Dedham EMS before being transported to the Framingham Barracks for booking. He has been charged with trespassing.

“In the interest of ensuring a fair trial, the Trial Court issued an order regarding the second Commonwealth v. Karen Read trial which restricts activities in the area of the Norfolk Superior Courthouse in Dedham (also known as the buffer zone),” State Police said in a statement. “The Trial Court charged Dedham Police along with the Massachusetts State Police with ensuring the integrity of the buffer zone through uniformed patrols.

State Police added, “Recognizing the unique nature of this mission, all sworn members assigned to the area of the Courthouse received training to ensure they understand their patrol responsibilities and can assist constituents who need guidance about their responsibilities under the order.”