JACKSONVILLE, Fla.— A north Florida mother has pleaded guilty to shaking her baby to death after the boy’s crying interrupted her game on Facebook.

Alexandra V. Tobias pleaded guilty to second-degree murder on Wednesday and remains jailed.

The Florida Times-Union reports that she told investigators she was angered because the boy was crying while she was playing the game FarmVille.

The paper also reports that she told investigators she shook the boy, smoked a cigarette to compose herself and then shook him again.

She will be sentenced in December. State guidelines call for 25 to 50 years, but a prosecutor said it could be shorter than that.

A telephone message and an e-mail sent by The Associated Press to her attorney weren’t immediately returned.