Woman faces charges in UNH student’s murder case

Authorities say she provided false alibi for suspect

Authorities believe Elizabeth “Lizzi” Marriott, a University of New Hampshire student, was strangled or suffocated.
Britney Atwood/Associated Press
Authorities believe Elizabeth “Lizzi” Marriott, a University of New Hampshire student, was strangled or suffocated.

A 19-year-old Portsmouth, N.H., woman was arrested Monday on accusations of helping cover up the killing in October of Elizabeth “Lizzi” Marriott, a University of New Hampshire student from Westborough, Mass.

Kathryn “Kat” McDonough was arrested and charged with hindering apprehension or prosecution and conspiracy to commit hindering apprehension or prosecution.

At the time of Marriott’s disappearance, McDonough was the girlfriend of Seth Mazzaglia, who has been charged with second-degree murder in connection with the death of Marriott.


Marriott’s father, Robert, received word of the second arrest in his daughter’s murder case shortly after 1 p.m. Monday.

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“I look at it as a positive sign that the police investigation is moving forward,” he said.

Marriott’s father said he did not know any details about any connection or relationship between McDonough and his daughter.

But he said he heard McDonough’s name in connection with the investigation months ago.

“I never heard of her name before Lizzi went missing,” he said.


Mazzaglia, 29, of Dover, N.H., has been charged with second-degree murder in the death of Marriott, a marine ­biology student in her first ­semester at the University of New Hampshire in Durham and a 2011 Westborough High School graduate and former junior prom queen.

Authorities believe Marriott, 19, was strangled or suffocated the evening of Oct. 9 in Mazzaglia’s Dover apartment.

Assistant Attorney General Peter Hinckley said the ­charges against McDonough allege that during an interview with police, she gave a false alibi for her and Mazzaglia’s whereabouts on the night of Oct. 9.

In addition, Hinckley said, McDonough gave false statements regarding her “lack of interaction” with Marriott.

Hinckley said McDonough was arrested at her place of work without incident.


McDonough’s bail was set at $50,000, but Mr. Hinckley said that amount would probably change when she is arraigned Wednesday in Derry District Court.

McDonough is still in custody, Hinckley said.

Mazzaglia was arraigned Oct. 15 on the second-degree murder charge.

He graduated from UNH six years ago with a bachelor’s degree in theater and has worked in various theater jobs and as a martial arts instructor.

Mazzaglia is being held without bail at the Stafford County House of Correction in Dover.

McDonough is a 2011 graduate of Portsmouth High School.

In 2011, Mazzaglia and McDonough starred in the Players’ Ring production of ­Lawrence Hennessey’s “Last Rites.”

New Hampshire officials have searched unsuccessfully for Marriott’s body in the waters off Peirce Island in Portsmouth.