A DeKalb County mother was found guilty Friday of two counts of involuntary manslaughter in connection with the death of two of her children in 2010.

Angel Johnson was also convicted of cruelty to children and making false statements because she lied about leaving three of her four children alone in a Stone Mountain apartment on Dec. 10, 2010, according to a news release from the office of the DeKalb County district attorney. She was sentenced to 35 years, 20 of which she must serve.

“The negligence of Angel Johnson led to the death of two of her young children who died a horrific death that was 100 percent preventable,” District Attorney Robert James said in a prepared statement.

On the night the children died, Johnson and her boyfriend, Keith Pinkney, locked the three children in a bedroom and went to a fast-food restaurant, according to the release. While they were gone, something in the bedroom got too close to a space heater, and caught fire. Aliyah Quarles, 4, and Devyn Quarles, 3, died from asphyxiation and injuries caused by the fire, according to the release. A 2-year-old in the room survived but was hospitalized with burns.

Pinkney, who also faces counts of child cruelty and giving false statements to police and involuntary manslaughter, was not tried with Johnson. His trial date has not yet been scheduled.