A First Nation chief asked the RCMP and Health Canada to investigate after four people in Esgenoôpetitj, formerly known as Burnt Church First Nation, overdosed on pills they bought and consumed.
One woman, 35-year-old Ann-Marie Lambert, died before paramedics could get her to hospital.
An autopsy will be performed to determine how Lambert, the mother of a young son, died.
The RCMP are continuing to investigate her death but say no foul play is suspected.
Alvery Paul, chief of the First Nation southwest of Neguac, said he heard about the overdoses, one after another, from late Tuesday afternoon into the evening.
Two people were treated in hospital and returned home. A third person was in critical condition for two days but is now responsive.
"People are in a shock of what's going on and they know where it was going and who's delivering it," Paul said.
Chief posts warning
There is speculation in the community that the pills may have been laced with fentanyl. At least one pill was blue, with the number five on it, and sold to the victims as a Percocet.
Paul posted a picture on Facebook of what is believed to be the pill along with a warning about drug abuse.
"We have to stop it and we really have to seriously look at it because it might affect another family, another child, another husband, another wife."
Paul said he is now trying to protect his community from a drug crisis and warns other communities to be careful as well.
He also encourages people to tell the RCMP what they know so others can be saved.
"It killed somebody and if somebody passed that drug to somebody, he's responsible for that person and what he done."
A crisis team is in the community trying to help those affected.
The chief added counsellors were swamped with friends and family of those affected. They remained at the community's wellness centre overnight Wednesday, helping those who needed it.
He also asked for help from Health Canada.
"We have them there for 24/7. Anybody, not just the family of what happened, other families out there that wants to come in talk because it's part of their friends. And she had a lot of friends in the community."
Funeral services for Lambert will be held Monday.