Woman admits she fatally stabbed her boyfriend in Dorchester apartment

Just moments before her murder trial was to begin, Valerie Cirilo-Perez, 26, admitted she plunged a knife into Anthony Sinclair's heart in their Nightingale Street apartment during a fight on Dec. 8, 2015, the Suffolk County District Attorney's office reports.

As a Suffolk Superior Court jury awaited opening arguments in her second-degree murder case, Cirilo-Perez pleaded guilty to manslaughter. Judge Kenneth Fishman then sentenced her to 9 to 14 years in state prison.

According to the DA's office:

Had the trial proceeded, [Assistant DA Matthew] Bradley would have presented evidence and testimony to prove that Cirilo-Perez and Sinclair were involved in a romantic relationship that was marked by prior incidents of domestic violence allegedly committed by both individuals, including an incident in which Cirilo-Perez stabbed Sinclair in the back. On Dec. 8, 2015, Sinclair and Cirilo-Perez - who was pregnant and outweighed the victim by more than 100 pounds - were involved in a verbal argument that escalated into a physical altercation during which Cirilo-Perez stabbed the victim with a small kitchen knife, piercing his heart. ...

Cirilo-Perez called 911 and was inside the apartment when first responders arrived. She made mutually inconsistent statements to investigators on the events leading up to the stabbing, prosecutors said, including a claim that Sinclair had come home drunk, which was refuted by toxicology testing performed as part of the autopsy that showed no alcohol in his system at the time of his death.