Ontario's provincial police watchdog announced Friday that it is now investigating a Hamilton police officer in connection with the death of 19-year-old Yosif Al-Hasnawi.

The news comes just weeks after two Hamilton paramedics who face charges in the Good Samaritan's death were fired by the city.

Al-Hasnawi was shot on Dec. 2, 2017. Police say the Brock University medical sciences student intervened when an older man was being accosted in central Hamilton. He and his brother had just stepped outside the Al-Mostafa Islamic Centre, where they'd been participating in a religious ceremony.

The intervention, police say, caused the perpetrators to turn their attention to Al-Hasnawi.

He died in hospital about an hour after the shooting. Bystanders said at the time that police and paramedics didn't seem to treat his injury with enough urgency.

The provincial Special Investigations Unit (SIU) announced Friday that due to media reports, SIU investigators started to look into "whether there was a basis to invoke the unit's jurisdiction."

Human rights activist Firas Al Najim, left, and Yosif Al-Hasnawi's younger brother, Ahmed Al-Hasnawi, hold a photo of Al-Hasnawi at a memorial at Hamilton City Hall. (Laura Clementson/CBC)

The SIU is called in whenever there are reports involving police where there has been a death, serious injury or allegations of sexual assault.

"Based on the results of those preliminary inquiries, which included medical evidence, the SIU can confirm that it is investigating the role of one Hamilton Police Service officer in relation to this incident," the SIU said in a news release.

Two witness officers have also been designated on the case, the SIU said.

Union files grievance after paramedics fired

Police have also charged two paramedics in connection with the incident. Steve Snively, 53, of Hamilton, and Chris Marchant, 29, of Whitby, Ont., have been charged with failing to provide the necessaries of life.

Mario Posteraro, president of OPSEU Local 256, said in an interview earlier this month that both paramedics have been fired, and the union will file a grievance over the "harsh and unjust action."

"The employer had a number [of] options it could have exercised while the criminal charges were being dealt with through the courts. Instead, they decided to throw two of their paramedics under the bus," he said in a statement.

Two men are also charged in Al-Hasnawi's death — Dale Burningsky King, 19, and James Matheson, 20. King is charged with second-degree murder. Matheson was originally charged with being an accessory after the fact. But according to a Hamilton Spectator report, that charge was withdrawn earlier this week. He is back in court on Oct. 30 for sentencing on a charge of obstruction of justice.

Al-Hasnawi's father and brothers are suing the Hamilton Police Service, the paramedic service and St. Joseph's Healthcare Hamilton, along with King and Matheson for their alleged roles in his death.

None of the charges have been proven in court.

adam.carter@cbc.ca