British Columbia's gang squad and the Abbotsford Police Department say a sensitive law enforcement intelligence document was posted on an online media site.
A statement from police and the Combined Forces Special Enforcement Unit says the document was part of a response to the ongoing gang war that has killed numerous people in the last several years.
Abbotsford police say in the statement that the naming of people in the document doesn't necessarily mean they are related to the shootings or that they are involved in illegal activity.
The statement says police have identified how the information was compromised and the document has since been removed from the unnamed media site.
Police say they are "actively connecting" with those who have been affected by the release of information.
The statement says the RCMP has also been called in to investigate, while notifications have been issued to both the privacy commissioner and the police oversight body.
"At this time, there is no information to indicate an increased risk to public safety stemming from the unauthorized release of information," the statement says.