The family of a Toronto teenager who was fatally shot after a standoff with police says it is “relieved” that the officer involved will be charged with second-degree murder.

The Special Investigation Unit, Ontario’s police watchdog, announced Monday that an arrest warrant has been issued for Const. James Forcillo in connection with the death of Sammy Yatim, 18, who was shot and killed on a Toronto streetcar in the early morning hours of July 27.

The SIU said arrangements have been made for Forcillo to surrender himself into custody on Tuesday morning.

“We have been waiting patiently and cooperating with the police investigation and want to hold accountable all those responsible for Sammy’s death,” Yatim’s family said in a statement.

“Our family hopes that the SIU investigation will continue looking into the actions of the supervising police officer(s) and the other officers in attendance for their lack of intervention in this tragedy,” the statement reads.

“We want to work now to ensure that Sammy’s blood wasn’t wasted and to prevent any other families from enduring such a tragedy. We would like to thank the public again for their continued support throughout this trying time for us.”

The SIU said Forcillo “has been the recipient of threats,” and so the agency will not be releasing the location of his planned surrender.

The earlier statement from the agency said that SIU director Ian Scott, “has reasonable grounds to believe that a Toronto Police Service (TPS) officer committed a criminal offence in relation to” Yatim’s death.

After he turns himself in, Forcillo will then be transported to Old City Hall court.

“Pursuant to the provisions of the Criminal Code, he will be detained in custody,” the agency said. “The Criminal Code allows an accused to have the detention order reviewed in Superior Court and seek bail at any point in time.”

The SIU is an independent body that probes incidents of serious injury or death involving police officers.

Since its inception in 1990, 10 other Ontario police officers have been charged with second-degree murder or manslaughter. Only one of them was convicted, but that was overturned on appeal.

Earlier Monday, Toronto Police Association president Mike McCormack said the union is “very disappointed” to learn of the charge, but also “not surprised.

“But what we do is we stand by due process,” McCormack told CP24. “Now that we’re into this process, the charges are going to be before courts and let’s see where the evidence leads. And let’s start talking about evidence and truth and facts instead of people just jumping to conclusions.”

Yatim’s final moments were caught on local surveillance video and cellphone images taken by passersby that were then posted on YouTube. The videos show Yatim, holding a knife, pacing back and forth on the empty streetcar as police shout, “Drop the knife.” Then, over the course of 13 seconds, nine shots ring out. A Taser was also used during the incident.

Forcillo was suspended with pay while the SIU conducted its investigation.

McCormack said Forcillo is “devastated” by the incident.

“This has not been an easy process for him,” McCormack said. “It’s been a lose-lose situation for everybody.”

In the days following the shooting, thousands of the city’s residents poured into the streets in protest. The shooting also sparked an online petition calling for criminal charges to be laid. Within days, the petition had more than 30,000 signatures.

Earlier this month, Ontario’s ombudsman announced he was launching a formal investigation into provincial guidelines issued to police for de-escalating conflict situations.

Andre Marin said his investigation will look at how police forces across the province train officers to respond to conflict situations, and whether the Ministry of Community and Correctional Services should consider implementing a province-wide standard.

Marin said his probe will also look at what became of recommendations that came out of coroners’ inquests and other reports into police shootings dating back to 1994. The investigation will take between six and 12 months.

Days after Marin declared his intentions, Toronto Police Chief Bill Blair announced that retired judge Dennis O’Connor will review use-of-force tactics by his officers.

"I believe that the public concern with respect to this matter and issues arising and concerns about our policies and our procedures, the training of our officers and the equipment that they use requires that I seek the help of Justice O'Connor," Blair said at a news conference.

The Police Services Act mandates that the chief conduct a review of the shooting because the SIU is involved. However, O’Connor’s probe will include other police shootings, as well as international standards for use-of-force training.

O’Connor was the associate chief justice of the Ontario Court of Appeal for 10 years, and led an inquiry into the tainted water scandal in Walkerton, Ont.

The professional standards branch of the Toronto force is also looking into Forcillo’s conduct during the incident.

With files from Andrea Janus and The Canadian Press