<P> When Cho 's friend Marietta Edgecombe betrays the group to Umbridge ( Cho herself while under the influence of the truth potion Veritaserum in the film ) , Marietta is cursed with pimples on her face as a result of Hermione 's casting a spell on the D.A. membership list . Later on , to prevent Harry 's expulsion and the incrimination of other members , Dumbledore claims responsibility for organising the group , then escapes when Ministry officials attempt to arrest him . Though the D.A. stops meeting following these events , three members -- Ginny , Neville and Luna -- join Harry , Ron and Hermione in the battle in the Department of Mysteries towards the end of the fifth book . In Harry Potter and the Half - Blood Prince , Neville and Luna are distraught due to the fact that the D.A. no longer exists . When Hogwarts is invaded by Death Eaters , they are among the members who join the Order of the Phoenix in the ensuing battle . </P>
<P> When Cho 's friend Marietta Edgecombe betrays the group to Umbridge ( Cho herself while under the influence of the truth potion Veritaserum in the film ) , Marietta is cursed with pimples on her face as a result of Hermione 's casting a spell on the D.A. membership list . Later on , to prevent Harry 's expulsion and the incrimination of other members , Dumbledore claims responsibility for organising the group , then escapes when Ministry officials attempt to arrest him . Though the D.A. stops meeting following these events , three members -- Ginny , Neville and Luna -- join Harry , Ron and Hermione in the battle in the Department of Mysteries towards the end of the fifth book . In Harry Potter and the Half - Blood Prince , Neville and Luna are distraught due to the fact that the D.A. no longer exists . When Hogwarts is invaded by Death Eaters , they are among the members who join the Order of the Phoenix in the ensuing battle . </P>
who told umbridge about dumbledore 's army in the book
who told umbridge about dumbledore 's army in the book
Marietta Edgecombe
Marietta Edgecombe