Marietta is brought to Dumbledore's office by Professor Umbridge. She hides her face in her hands as they enter the office as it is horribly disfigured by a series of close-set purple pustules that are spread across her nose and cheeks to spell the word 'SNEAK'. She pulls the neck of her robes up to her eyes and refuses to talk, shaking her head frantically. According to Umbridge, Marietta came to her office shortly after dinner that evening and told her about the meeting in the Room of Requirement. After the hex came into operation, Marietta was so distressed by her reflection in Umbridge's mirror that she refused to say any more.
Marietta's memory is secretly modified by Kingsley Shacklebolt during the interview, and she subsequently denies any knowledge of meetings that occurred after Educational Decree Number Twenty-four was implemented. When she continues to deny this during Umbridge's questioning, she is shaken viciously by the professor. She is only released when Dumbledore and Kingsley intervene. After Dumbledore escapes the office, Marietta is escorted back to her dormitory by Professor McGonagall.