RIVERSIDE (CBSLA) — Federal officials say the mother of one of the shooters in the 2015 San Bernardino terrorist attack has agreed to plead guilty to destroying evidence related to the shooting.

Rafia Sultana Shareef, also known as Rafia Farook, reached a plea deal with federal prosecutors in connection with the ongoing investigation into the attack on a company Christmas party at the Inland Regional Center in San Bernardino on Dec. 2, 2015.

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Farook and Malik in Chicago July 27, 2014 (credit: U.S .Customs and Border Protection)

According to the plea agreement, the shooters Syed Rizwan Farook and his wife, Tashfeen Malik, left the Redlands home they shared with Shareef that morning, telling her they were going to a medical appointment. Instead, Farook and Malik took a black SUV that had been rented a few days prior to the Inland Regional Center.

Farook put a bomb in a conference room where his coworkers were about to hold a Christmas party, according to the Department of Justice. Authorities said the couple left, then returned just before 11 a.m. dressed in tactical gear and with high-powered firearms, opening fire on people outside and inside the venue. Fourteen people were killed and 22 others wounded in the shooting.

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A few hours later, after leaving the mass shooting, the couple got into a shootout with police that wounded one officer and killed them, authorities said.

According to the Justice Department, when Shareef learned of the shooting and that her son had been identified as one of the suspects, she went into her son’s bedroom and grabbed a map and fed it into a shredder. She admitted to federal investigators that she knew her son had created the map and she believed it was directly related to his planning of the attack.

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The felony charge carries a maximum statutory sentence of 20 years in federal prison, but according to the plea agreement, 66-year-old Shareef will serve no more than 18 months. She is scheduled to make her first appearance in federal court on March 16.