York Regional Police have laid manslaughter and drug-related charges in connection with two separate deaths resulting from the use of fentanyl.

The first incident occurred at a residence near Hoover Park Drive and Ninth Line in Whitchutch-Stouffville around 6:50 p.m. on Feb. 2.

When officers arrived at the scene, police found a deceased 28-year-old woman.

Investigators later determined that the victim died as a result of the use of fentanyl. On May 23, police arrested a suspect they believe provided the woman with the drug.

Three additional people were taken into custody on June 12. Investigators say that the suspects were found to be in possession of both fentanyl and cocaine.

A suspect police have identified as 24-year-old Clair Kozlowski from Mississauga has been charged with manslaughter, criminal negligence causing death and trafficking fentanyl.

Mississauga resident Jovane Jolly, 27, has been charged with numerous drug-related offenses, criminal negligence causing bodily harm and conspiracy to commit an indictable offence.

Michael James Matthews, 34 and David Winn, 65, are also facing drug-related charges.

The second incident occurred on Feb. 25 at about 2:50 a.m. in Markham.

Police were called to a residence near 14th Avenue and Kennedy Road after a 33-year-old man was found dead.

According to investigators, it was later determined that the victim had died as a result of the use of drugs laced with fentanyl.

On June 18, police arrested a suspect they allege sold the drugs to the victim. Police say the suspect was found with substances believed to be cocaine and heroin.

Richmond Hill resident Michael Calvan has been charged with manslaughter, criminal negligence causing death, trafficking in a schedule 1 substance and possession for the purpose of trafficking.

None of the charges have been tested in court.

“This is the third recent investigation where an individual has been charged with manslaughter in York Region after a death has occurred as a result of fentanyl,” police said in a news release issued Thursday.

“It is now well known that fentanyl has caused thousands of deaths across Canada. Anyone trafficking, sharing or providing or lacing other drugs with fentanyl is putting the lives of others at risk and can expect to face serious criminal consequences.”

Police are asking anyone with information about the incident to contact investigators or reach out to Crime Stoppers anonymously.