A 13-year-old northwest Wisconsin girl who went missing in October after her parents were killed has been found alive, authorities said Thursday.

The Barron County Sheriff's Department said on its Facebook page that Jayme Closs has been located and that a suspect was taken into custody.

Sheriff Chris Fitzgerald said the sheriff's office in Douglas County, about 110 kilometres north of Barron County, located the girl. A suspect was apprehended a short time later. The statement did not say where Jayme was found or give any further information about the suspect.

The sheriff's office plans to hold a news conference Friday at 11 a.m. ET to discuss the case.

The girl has been missing since her parents, James and Denise Closs, were found shot to death Oct. 15 at the family's home near Barron. Investigators said Jayme was quickly ruled out as a suspect.

A Barron County, Wis., sheriff's vehicle was parked outside the home where James Closs and Denise Closs were found fatally shot on Oct. 15. (The Associated Press)

Detectives pursued thousands of tips, watched dozens of surveillance videos and conducted numerous searches in the effort to find her.

Her grandfather Robert Naiberg told the Minneapolis Star Tribune that the teen was being treated at a hospital before being reunited with family.

Lacey Naiberg, a cousin of Closs's, wrote on Facebook that "there are no words to describe" the feeling of having so many people come together to help. She asked people to continue to pray for "Jayme's well-being and our families healing."

Barron Mayor Ron Fladten said knowing the teen has been found is "unbelievable. It's like taking a big black cloud in the sky and getting rid of it and the sun comes out again."