DERRY, N.H. (AP) — A New Hampshire woman lied to investigators about her whereabouts and involvement in the disappearance and death of a college student her boyfriend is accused of killing, prosecutors said Wednesday.

Kathryn McDonough is charged with conspiracy and hindering the apprehension or prosecution of those responsible for the death of 19-year-old Elizabeth "Lizzi" Marriott in October. McDonough, also 19, appeared in Derry District Court via a video link from jail, where she has been since her arrest Christmas Eve.

Judge John Coughlin set bail at $35,000 and set a condition of McDonough's release that she live with her parents in Portsmouth.

Marriott, a University of New Hampshire sophomore from Westborough, Mass., who was living with relatives in Chester, vanished Oct. 9 after telling family members she was going to visit friends in Dover and would return home before midnight. Her cellphone was last used just after 10 p.m. that night. Her body has yet to be found.

Four days after Marriott was last heard from, 30-year-old Seth Mazzaglia of Dover was charged with second-degree murder in her death. Prosecutors say he either strangled or suffocated Marriott.

In arguing Wednesday to continuing holding McDonough on a $50,000 cash bond, Assistant Attorney General Peter Hinckley said Marriott's body still has not been found "in no small part because of Ms. McDonough's participation in the alleged conspiracy."

Hinckley said McDonough made "an intentional attempt to disrupt the criminal process."

McDonough and Mazzaglia conspired to give investigators a false alibi about their whereabouts the night of Oct. 9 and told them they had no interaction with Marriott that night, prosecutors said in court documents.

Hinckley said he is seeking an extension until late February to get a grand jury indictment of Mazzaglia so investigators can interview additional witnesses and process evidence.

Prosecutors won't say what evidence they have to support their convictions that Marriott is dead and that Mazzaglia killed her.

The arrest warrant affidavits for both McDonough and Mazzaglia remained sealed and Hinckley would not elaborate Wednesday on the alibi they provided or other details of the investigation into Marriott's death.

Hinckley said McDonough was Mazzaglia's girlfriend at the time of Marriott's disappearance.

McDonough's lawyer, Ryan Russman, who sat alongside his client during the arraignment, said she is "obviously concerned. Who wouldn't be?" Her parents, Peter and Denise McDonough, declined to comment when they left the brief court hearing.