(CNN) An Ohio woman who wrote letters to Dylann Roof and admired the Columbine High School shooters was sentenced to 15 years in prison Wednesday for her role in planning two terrorist attacks, according to the US Attorney's Office for the Northern District of Ohio.

Elizabeth Lecron is accused of domestic terror threats and corresponding with Dylan Roof.

Elizabeth Lecron was arrested last December , accused of plotting an attack at a Toledo bar and purchasing bomb-making materials to blow up a pipeline in Georgia. She pleaded guilty to terrorism charges in August. Upon release from prison, she'll be subject to lifetime supervision by a federal court as part of her sentence.

An attorney for Lecron declined to comment.

Lecron's co-defendant, her boyfriend, Vincent Armstrong, also pleaded guilty to charges stemming from his participation in the plot, the USAO said in a statement. He'll be sentenced on December 10.

According to the USAO, Lecron and Armstrong were "immersed" in an online group called the "True Crime Community," which "fixated and lionized mass murderers and posted extremely graphic images, videos, and sayings."

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