CHICAGO (CBS) — A 49-year-old Chicago man is going off to prison for the next 27 years, for breaking into his girlfriend’s home on Valentine’s Day two years ago and attacking her.

Derrick Williams pleaded guilty to attempted first-degree murder and home invasion in the Feb. 14, 2009, attack, and was sentenced Monday, according to the Cook County State’s Attorney’s office.

Prosecutors said Williams and the victim had dated briefly, but had broken up nearly a year after the attack. The ex-girlfriend was home with her daughter and son when Williams broke into her apartment and stormed into her bedroom, where he punched her and stabbed her with a kitchen knife, prosecutors said.

The victim’s daughter tried to intervene, but Williams slashed her in the face, leaving a cut that ran from her hairline to the middle of her cheek, prosecutors said.

Afterward, Williams dragged both the victim and her daughter to the living room and went on stabbing the woman. The daughter and son called police, but Williams ran off, prosecutors said.

The daughter and son’s ages were not specified.

Police eventually caught up to Williams, who was found covered in blood from the attack, with the knife he had used still in his back pocket.

Williams admitted to the crime, and forensic tests matched the blood on his clothes and the knife with that of the victim, prosecutors said.

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