AG IDs Ashland officer who shot, killed driver during traffic stop

The state Attorney General’s Office identified Ashland Police Sgt. Nicholas Shannahan as the officer who shot a driver during a traffic stop last month in Ashland, according to a press release on Friday. Demitri Zimmer, 24, of Laconia, died in the shooting.

Another officer who was shot and wounded during the April 20 shooting was identified as Mason Dalphonse, who is at home and healing from his wounds, according to the press release. Dalphonse was treated at Concord Hospital-Concord that night for a gunshot wound, and released from the hospital the following day.

Shannahan has been with Ashland Police for about three years, and Dalphonse has been with the department for two years.

On the night of April 20, Ashland Police stopped Zimmer’s vehicle on Main Street near the fire station. During the stop, Zimmer allegedly pulled out a gun, and exchanged fire with police.

Zimmer died at the scene, and his cause of death was multiple gunshot wounds, according to an autopsy by the Officer of the Chief Medical Examiner, who determined the manner of death was homicide.

Homicide is defined by the Chief Medical Examiner’s Office as “the killing of one person by another.”

“The exact circumstances surrounding the incident remain under investigation,” the Attorney General’s Office stated in a release on Friday. “No further updates are expected until the investigation is complete.”

Court records show Zimmer was scheduled to appear in Grafton Superior Court on Aug. 17, in a pre-trial hearing for a felony charge of reckless conduct with a deadly weapon. That incident took place in Holderness on June 29, 2025, and Zimmer was indicted on Nov. 21, 2025.

Ashland Chief William Ulwick said in the days following the incident the officer who was shot was on a paid leave of absence, and another officer was waiting for the investigation to take place.

Ulwick said he and Lt. Nicholas Raymond are team leads for the Lakes Region Critical Incident Stress Management Team and the Peer Support Team, as well as being president and vice president of the Responders Together NH officer wellness group. He told The Daily Sun they have an abundance of resources set up for the officers involved, as well as any other Ashland officer affected by the shooting.

This was the second police shooting in the Lakes Region within a month, as Northfield Police Officer Nikolas Ballentine shot and killed 27-year-old Megan Whiting on April 6, during a domestic disturbance call.

Whiting allegedly had a knife close to an injured female resident, and after police told her more than once to drop the weapon, Ballentine shot her, according to the Attorney General’s report. She died at the scene, and no police or other citizens were physically injured.

Ballentine is also on leave while the Attorney General’s Office conducts an investigation.