Ontario's police watchdog is now investigating the death of a 19-year-old man in Brampton, who died after he allegedly sold a counterfeit item to two Toronto police officers earlier this year.

According to a Special Investigations Unit (SIU) news release issued Thursday, the incident happened in April, though the SIU wasn't notified about it until this week.

The SIU says that on April 26, a 19-year-old from Brampton met with two people in the area of Bellchase Trail and Highway 50 to "conduct a business transaction." Those two people were Toronto police officers, according to the news release. The SIU said it's unclear whether or not they were on duty or off duty at the time.

Shortly after the transaction was completed, the officers "realized the item purchased was counterfeit," according to the news release.

In an emailed statement to CBC News, SIU spokesperson Loida Pedro said the agency "is not in a position to identify the counterfeit item sold."

The two police officers then chased down and caught the man. "The details of that interaction are not yet known," the SIU said.

Sometime later, the 19-year-old's friends picked him up and "noticed he appeared unwell," according to the news release. They took him to hospital where he later died.

The man's cause of death is unknown at this time, the SIU said. No other details were provided.

According to Toronto police spokesperson Connie Osborne, Peel Regional Police first notified Toronto police about the incident on Aug. 24.

"TPS then immediately notified SIU, within an hour, that same day. The service is fully co-operating with SIU," Osborne said.

According to the SIU's website, all Ontario police services have a legal obligation to immediately notify the SIU of any incidents of serious injury, allegations of sexual assault, or death involving their officers.

Const. Akhil Mooken, spokesperson for Peel police, told CBC News that Toronto police officials weren't notified until recently because information that "revealed the identities" of the two police constables involved in the incident was only received within the last week.

Mooken would not answer any questions about the victim's identity, if he had any injuries, what his cause of death was, and why his cause of death has not been released, four months on.

"As this matter is now being investigated by the Special Investigations Unit, we are unable to share any further details on this incident at this time," Mooken said.

Pedro said that as the SIU was only notified about the death this week, investigators are "currently arranging" interviews.

The SIU is asking anyone who might have information about the incident to contact the lead investigator at 1-800-787-8529, and for anyone who may have video evidence related to this incident to upload that video through the SIU website.