TORONTO -- The Canadian Press has learned that a former Ontario nurse accused of killing eight seniors in her care is expected to plead guilty to first-degree murder charges in their deaths at a court appearance on Thursday.

Elizabeth Wettlaufer currently faces a total of 14 charges, including eight counts of first-degree murder, four counts of attempted murder and two counts of aggravated assault.

Police have alleged those crimes involved the use of certain drugs and took place over the last decade in three Ontario long-term care facilities where Wettlaufer worked as a registered nurse, and at a private home.

A source close to the case tells The Canadian Press that Wettlaufer is scheduled to plead guilty to eight counts of first-degree murder in a Woodstock, Ont., court on Thursday.

The source says an agreed statement of facts and a video of Wettlaufer confessing is expected to be filed in court.

Wettlaufer's defence lawyer did not respond to requests for comment on the expected development.

A spokeswoman with Ontario's Ministry of the Attorney General said "significant developments" are expected in the case on Thursday, but did not provide further details.

Sgt. Dave Rektor of the Ontario Provincial Police, one of the forces involved in the multi-jurisdictional investigation, declined comment.

The police investigation into Wettlaufer, 49, began last September after Toronto police became aware of information she had given to a psychiatric hospital in Toronto that caused them concern, a police source has told The Canadian Press.

In October, Wettlaufer was charged in the deaths of eight residents at nursing homes in Woodstock and London, Ont. In those cases, police alleged Wettlaufer used drugs to kill the seniors while she worked at the facilities between 2007 and 2014.

In January, Wettlaufer faced six additional charges related to seniors in her care. Court documents allege Wettlaufer injected those six alleged victims with insulin.

Records from the College of Nurses of Ontario show Wettlaufer was first registered as a nurse in August 1995 but resigned Sept. 30, 2016, and is no longer a registered nurse.