COLUMBUS, Ohio (AP) — The Ohio Attorney General’s Office and a county sheriff have sent an alert to authorities in six southern states in an attempt to identify a female believed to have been slain by a convicted serial killer.

The Attorney General’s Office on Tuesday said Shawn Grate confessed to killing a female in Marion County in 2004 or 2005. Her body was found in 2007. The female’s age has been estimated at between 15 and 30 years old.

An isotope analysis of the female’s bones by the University of South Florida show she was likely born in one of the states receiving the alert, which include Alabama, Florida, Georgia, Louisiana, Mississippi and Texas.

The 41-year-old Grate was sentenced to death last week for killing two women in Ohio’s Ashland County.