CONCORD, N.H. — A New Hampshire woman charged with lying to investigators about the disappearance of a University of New Hampshire sophomore last fall has pleaded guilty.

Nineteen-year-old Kathryn McDonough of Portsmouth pleaded guilty Thursday to hindering the prosecution, conspiracy and tampering with a witness.

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McDonough’s ex-boyfriend – Seth Mazzaglia is charged with strangling 19-year-old Elizabeth “Lizzi” Marriott last October.

The couple admitted to investigators that they dumped her body into the waters off Peirce Island in Portsmouth. It has never been recovered.