A second day of disturbing testimony has come to a close in the trial of a New Hampshire man charged with raping and killing a 19-year-old college student.

Prosecutors say 31-year-old Seth Mazzaglia became enraged when Elizabeth “Lizzi” Marriott twice refused his sexual advances on Oct. 9, 2012, at his Dover apartment.

Mazzaglia’s ex-girlfriend, Kathryn McDonough, testified that he sneaked up behind Marriott as the two women watched a movie. She said he choked Marriott with a rope, then raped her.

“She was sitting right next to me and he moved up close behind her, he was still on the bed. And he wrapped the rope over her head and around her neck and he started pulling on it,” McDonough said. “It looked like he was pressing his knee against her back and pulling the rope towards him as he held her still with his knee.”

McDonough, who was on the stand for the second day in a row, said she helped throw Marriott’s body in a river. It has never been found.

Mazzaglia’s lawyers say McDonough killed Marriott, of Westborough, Massachusetts, during consensual rough sex. They will get an opportunity to question McDonough on Thursday.

McDonough has pleaded guilty to hindering prosecution and is serving 1 1/2 to 3 years in prison.

The Associated Press contributed to this report.

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