RCMP said a 54-year-old man is in custody and there is no danger to the community.
One woman and two men have been killed, police said.
At least one home in the northern B.C. community was behind police tape on Tuesday morning.
No other details have been released, but Burns Lake Mayor Luke Strimbold posted a message last night on his Facebook account.
"Tonight I ask for each of us to think about and say a prayer for the families that are faced with questions and sadness," said the message.
"Many families have had difficult challenges and losses over the last few days and month. Let's unite together in thoughts and prayers for the safety and well-being of all our community members."