DOVER, N.H. (AP) — Newly unsealed documents say a man charged with killing a University of New Hampshire student in October initially told investigators that someone else strangled her then later said he accidentally killed her during a consensual sex act, which prosecutors dispute.

Thirty-year-old Seth Mazzaglia is charged with killing 19-year-old Elizabeth "Lizzi" Marriott during an attempted sexual assault on Oct. 9. Prosecutors say it was not consensual.

A public defender representing Mazzaglia has declined to comment on the indictments.

Police documents in the case were unsealed Monday.

Foster's Daily Democrat reported that Mazzaglia described several scenarios when questioned about the death, including that he had come home and found her dead, with his girlfriend and another couple in his apartment. He later said he used a rope to strangle Marriott while they had sex.

The police affidavit also includes Mazzaglia's account of dumping Marriott's body in the Piscataqua River. It has not been recovered.

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