Rafia Sultana Shareef, the mother of one of the shooters in the 2015 San Bernardino terrorist attack, has agreed to plead guilty to destroying evidence — apparently a map — related to the attack, federal prosecutors said Tuesday.

The 66-year-old Corona woman agreed Monday to plead guilty to one count of alteration, destruction and mutilation of records, the U.S. Attorney’s Office for the Central District of California said in a statement.

Federal prosecutors said Shareef was living at a Redlands residence with her son Syed Rizwan Farook; his wife, Tashfeen Malik; and the infant child of Farook and Malik on the day of the attack, Dec. 2, 2015.

Hours after the attack that left 14 people dead and 22 injured at the Inland Regional Center in San Bernardino, Shareef went into her son’s bedroom, grabbed at least one document that appeared to be a map and fed it into a shredder, prosecutors said.

The terrorist attack by Syed Farook and Malik ended around 11:01 a.m. that day, and Shareef learned about it between 11:43 a.m. and 3:06 p.m., prosecutors said.

Prosecutors didn’t say in court documents what the map may have depicted and a spokesman for the U.S. Attorney’s Office declined comment on that question. An attorney for Shareef, Charles Swift, could not immediately be reached for comment.

Shareef’s plea agreement said she was watching the infant child when one of her family members arrived at the residence in Redlands to pick her and the child up.

“(Shareef) and (the family member) discussed their shared belief that Farook and Malik had perpetrated the attack at the IRC,” the plea document says.

“Prior to leaving the residence, (Shareef) went into the bedroom of Farook, Malik and their infant, grabbed at least one document that appeared to be a map, and fed the document into a shredder,” the agreement says.

The plea says Shareef knew the document had been made by Farook, and she believed that it was directly related to Farook and Malik’s planning of the attack at the IRC.

“Once she pleads guilty to the felony charge, Shareef will face a maximum statutory sentence of 20 years in federal prison,” the U.S. Attorney’s Office said in its statement. “But the plea agreement contemplates a sentence of no more than 18 months.”

Shareef’s son and Malik died in a shootout with law enforcement the day of the attack.

Shareef, also known as Rafia Farook, is scheduled to make her initial appearance in federal court in Riverside on March 16.

Tuesday’s announcement of an agreement for a guilty plea is the latest development in the aftermath of the shooting.

In another pending case, Enrique Marquez Jr., 28, wants to withdraw his guilty plea to conspiring to supply material to terrorists.

Attorneys argued the case in a two-day hearing in late January. U.S. District Court Judge Jesus G. Bernal said he was inclined to deny Marquez’s withdrawal motion, but a final ruling hasn’t been issued.

San Bernardino Sun staff writer Sean Emery contributed to this story.