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Ex-girlfriend of alleged killer in N.H. says ‘I’m not lying’

Kathryn McDonough continued her testimony in the Seth Mazzaglia trial at Strafford County Superior Court in Dover, N.H., on Monday.
Kathryn McDonough continued her testimony in the Seth Mazzaglia trial at Strafford County Superior Court in Dover, N.H., on Monday.Associated Press

DOVER, N.H. (AP) — The ex-girlfriend of a man charged with raping and strangling a 19-year-old University of New Hampshire student agreed on cross-examination that she lied persistently in the days and months after the killing, but on Monday she maintained that she isn’t lying to jurors now.

Seth Mazzaglia, 31, is charged with first-degree murder in the October 2012 death of Elizabeth ‘‘Lizzi’’ Marriott, of Westborough, Massachusetts.

Kathryn ‘‘Kat’’ McDonough, the state’s star witness, originally told defense investigators that she and Marriott were engaged in rough sex involving restraints when Marriott died. She said she initially lied to protect the 31-year-old Mazzaglia but changed her story after being given immunity from prosecution.


She has testified that Mazzaglia killed Marriott after she twice rejected his sexual advances. The pair tossed Marriott’s body in a river. It has never been found.

Defense attorney Joachim Barth peppered McDonough during a third day of cross-examination, trying to show she lied during grand jury testimony and was now lying to jurors.

‘‘I'm not lying to them,’’ she replied softly but firmly.

Barth tried to establish that she was the dominant one in their sexual relationship.

McDonough agreed she created a profile and solicited women on fetish websites but said it was because Mazzaglia wanted another sexual partner and thought women would respond better to an ad from another woman.

‘‘I felt like I had no other choice,’’ she testified. ‘‘I would have been happy with just him. That’s all I wanted.’’

McDonough said she came into the relationship as a bisexual and was open to a relationship with a woman but maintained Mazzaglia was driving the campaign to bring other women into their relationship.

It was McDonough’s fifth day on the witness stand and third under cross-examination. Many of her answers have been rambling but she has kept her composure under Barth’s questioning, which has included feigned incredulity and a sometimes mocking tone.


Monday’s testimony was saturated with questions about sexual acts and solicitations. Jurors showed little expression and some appeared bored, resting chins in their hands.

McDonough is expected to be back on the stand Tuesday.

More coverage:

Witness says she wanted to protect murder defendant

Defense lawyers challenge ex-girlfriend’s story at N.H. trial

Ex-girlfriend describes rape, murder of UNH student

Suspect’s ex-girlfriend describes killing of UNH student