According to two people familiar with the situation, Donald Trump has told people close to him that he’s getting his lawyers to look into the Mary Trump matter, to explore what could be done in the way of legal retribution—or at least a threat—likely in the form of a cease and desist letter. One of the sources with knowledge of the situation said that in the past couple of days, the president appeared irked by news of her book and at one point mentioned that Mary had signed an NDA years ago.

Mary Trump signed an NDA following a 2001 settlement after litigation disputing Fred Trump’s estate, according to people familiar with the matter. That NDA states she is not allowed to publish anything regarding the litigation or her relationship with Donald, Maryanne and Robert.

It’s not clear what type of response the president or his personal legal team will ultimately pursue. But his administration and his outside counsel have been busy during this tumultuous election year—one already ravaged by a cratered economy, a mass protest movement against police brutality and institutional racism, and the coronavirus pandemic—combating other new manuscripts and memoirs authored by top Trump associates turned bitter enemies.