A Niagara-area police officer who was shot and seriously wounded, allegedly by a fellow officer, has himself been charged in connection with the shooting.

Investigators with the Ontario Provincial Police allege Const. Nathan Parker of the Niagara Regional Police Service (NRPS) resisted arrest, assaulted an officer and committed assault with a weapon during the altercation that led to him being shot on Nov. 29, 2018.

Parker was arrested Wednesday morning, almost two months after the other officer, Det.-Sgt Shane Donovan, was charged by Ontario's Special Investigations Unit with attempted murder, aggravated assault and assault with a weapon.

The charges against Parker shed some light on the puzzling shooting that happened while a group of officers were investigating a collision from a few days before, at a crossroads in Pelham, Ont., a rural community about 20 kilometres west of Niagara Falls.

They suggest Donovan was trying to take Parker into custody.

Asked what led to the charge of resisting arrest, NRPS Chief Bryan MacCulloch said at a Wednesday afternoon news conference he wasn't privy to the evidence the OPP was relying on.

Donovan, who headed up the collision reconstruction unit, is alleged to have fired his gun multiple times. Parker was seriously injured and airlifted to Hamilton General Hospital, according to the SIU.

The puzzling shooting happened while a group of officers were investigating a collision from a few days before, in the rural community of Pelham, Ont. (Samantha Craggs/CBC)

OPP investigated at chief's request

Donovan is suspended with pay. Parker is still off work and recovering from his injuries.

Parker is a 28-year veteran of the force, according to the NRPS. In that time, he has reportedly faced multiple disciplinary hearings under the Police Services Act.

The OPP began its investigation after a request from the NRPS chief.

This is not over. Not for our members. Not for the community and not for the officers or their families.​​​​ - NRPS Chief Bryan MacCulloch

"In this case, because it was two of our members, I felt that it was most appropriate and provided an unbiased and impartial investigation to have that done by an outside agency," said MacCulloch.

The SIU investigates when someone is seriously injured by a police officer. But, MacCulloch explained, its investigation would focus on Donovan's actions alone. Therefore, a broader investigation was necessary to consider the actions of all involved.

MacCulloch said the shooting has had a significant impact on the service, which is still coming to terms with what happened and is encouraging officers and staff to access support.

"This is not over. Not for our members. Not for the community and not for the officers or their families," he said.

Parker, 52, is scheduled to appear in court in St. Catharines on June 10.