A New Hampshire woman is free after serving a three-year prison sentence for luring a co-worker to her apartment in 2012 as a sex offering to her domineering boyfriend, then helping him dispose of the co-worker's body after authorities say he strangled and raped her.

Corrections spokesman Jeff Lyons says Kathryn "Kat" McDonough was released from the Goffstown women's prison at 12:05 a.m. Saturday.

The 22-year-old pleaded guilty in 2013 to lying about the death of 19-year-old Elizabeth "Lizzi" Marriott, of Westborough, Massachusetts. She testified against Seth Mazzaglia (muh-ZAYL'-ee-uh), saying their sexual relationship included bondage and sadomasochism. He's serving a sentence of life without parole.

McDonough first told investigators that Marriott died during rough sex between them. After getting immunity from prosecution, she changed her story, saying Mazzaglia killed Marriott after she rejected him.