A 49-year-old former nurse has been charged with eight counts of first-degree murder connected to the deaths of residents in the southwestern Ontario nursing homes in which she worked.

Elizabeth Tracey Mae Wettlaufer is alleged to have killed elderly residents in care homes both in Woodstock, Ont., and London, Ontario Provincial Police announced in a news conference Tuesday.

Seven of the victims died after they received a fatal dose of medication while in the nursing home, police said. The victims are alleged to have been killed between 2007 and 2014.

Police launched an investigation into several deaths in London, Woodstock and in Oxford and Brant counties on Oct. 14.

A statement from Caressant Care Nursing Homes confirmed earlier that the investigation involves a registered nurse who worked in Woodstock — a community roughly halfway between London and Hamilton — but who has not been with Caressant for two and a half years.

CBC News has live coverage below of the police news conference.