CONCORD, N.H. (CBS) – She just graduated from high school within the last year and now finds herself in the middle of a high-profile disappearance and murder case in New Hampshire.

19-year-old Kathryn McDonough is the girlfriend of 30-year-old Seth Mazzaglia, the man accused of murdering UNH college student Lizzi Marriott in early October, and she is now facing charges herself.

WBZ NewsRadio 1030′s Carl Stevens reports

“She’s obviously caught up in a very serious investigation,” said McDonough’s attorney Ryan Russman.

Prosecutors say McDonough hindered the investigation by lying to authorities.

“It’s alleged that about October 12 she gave a statement to investigators investigating Ms. Marriott’s disappearance and gave a false alibi as to her and Seth Mazzaglia’s whereabouts on the day in question October 9th and also gave a false alibi as to their interactions with Ms. Marriott,” said Peter Hinckley, Assistant New Hampshire Attorney General.

McDonough was arrested Christmas Eve. She is charged with two felonies in connection with hampering the investigation but she is not charged with harming Lizzi.

“We’re talking about an allegation of deception, not an allegation of murder,” said Russman.

Outside the jail today where McDonough is being held, her mother declined to talk about the case.

“You know as much as I but thank you,” said McDonough’s mother.

McDonough’s family has had little contact with their daughter since she moved out in February to live with Mazzaglia.

Marriott’s body has not been found despite many searches.

Marriott’s mother declined to talk about this latest development when reached by phone Wednesday.