Chelmsford, MA — Chief Colin Spence is proud to announce the promotion of two members of the Chelmsford Police Department. Sergeant Nicholas Ziminsky has been promoted to the rank of Lieutenant, and Officer Nicholas Thayer has been promoted to the rank of Sergeant. Both officers have demonstrated outstanding leadership, professionalism, and dedication to serving the Chelmsford community.
The official swearing-in ceremony was held on January 5, 2026, in the Chelmsford Police Department Community Room, surrounded by family, friends, and colleagues.
Lieutenant Nicholas Ziminsky began his career with the Chelmsford Police Department in 2006 and was promoted to Sergeant in 2022. Throughout his career, Lieutenant Ziminsky has played a vital role in department training and operations. Prior to his promotion to Lieutenant, he served as the head of the department’s Training Division, overseeing use-of-force and defensive tactics instruction and ensuring officers were trained to the highest standards. Lieutenant Ziminsky is also a member and leader within the NEMLEC SWAT Team, responding to some of the most dangerous and complex incidents in Middlesex County. In addition to his law enforcement career, he proudly served eight years in the United States Coast Guard, including deployment during Operation Iraqi Freedom. Lieutenant Ziminsky has received multiple Awards for Outstanding Performance of Duty and is widely respected for his calm demeanor, professionalism, and strong commitment to officer safety.
Sergeant Nicholas Thayer joined the Chelmsford Police Department in 2018, after previously serving with the Townsend Police Department. In a relatively short time, Sergeant Thayer has distinguished himself as a highly motivated and capable leader. He is a member of the NEMLEC SWAT Team, a Field Training Officer, and a Defensive Tactics instructor. Sergeant Thayer has received multiple commendations, including an Award for Valor during an active shooter incident, an Award for Lifesaving, and an Award for Outstanding Performance of Duty, reflecting his courage, skill, and dedication. Beyond his law enforcement duties, Sergeant Thayer volunteers as a coach at Chelmsford High School, where he has made a positive and lasting impact on local youth both on and off the field.
“These promotions reflect the exceptional leadership, character, and service that both Lieutenant Ziminsky and Sergeant Thayer bring to our department every day,” said Chief Spence. “Their commitment to training, teamwork, and the Chelmsford community makes our department stronger.”
The Chelmsford Police Department congratulates Lieutenant Ziminsky and Sergeant Thayer on their well-earned promotions and thanks them for their continued service to the community.