The body of 19-year-old Lizzi Marriott was never found but her accused killer appeared in court Wednesday as the murder trial against him began.

The New Hampshire Attorney General says they know what happened when Marriott was killed back in 2012 while she was invited to spend time with accused killer Seth Mazzaglia and his girlfriend Katherine McDonough.

Prosecutors say Marriott, Mazzaglia and McDonough were engaging in kinky sex when the University of New Hampshire student was killed.

“He demanded another female to dominate and he, the master, was not to be denied,” prosecuting attorney Peter Hinckley said.

The state says Marriott agreed to play strip poker with the couple as a joke, but that when she denied Mazzaglia’s sexual advances he went on the attack.

“The defendant threw that rope around Lizzi’s neck and yanked back hard,” Hinckley said.

The defense admits Mazzaglia witnessed the crime, they even say he took steps to cover up her death, but they deny that he was the one who killed her.

“You will likely find him accountable, and he accepts that, but he did not cause Ms. Marriott’s death,” defense attorney Joachim Barth said.

Marriott’s family, including her father, was in court for the opening statements but the judge has asked them not to speak during the trial.

McDonough, who is already doing up to 3 years for the cover-up of Marriott’s death and the disposal of her body, is expected to testify at the trial.

Join our Newsletter for the latest news right to your inbox