Answer:
He says that Carl is blackmailing him and this is happening because Carl is likely to know about the Jews' hiding place.
Step-by-step explanation:
"Anne Frank" is the play that seeks to reproduce the story told in the book "The Diary Of a Young Girl" where Anne Frank tells how she, along with her family and other Jews, spent three years hiding in a building, trying not to taken to the Nazi concentration camps.
Within this story we met Mr. Kraler, an Austrian who helped the hidden Jews to obtain supplies and other products necessary for their survival. Mr. Kraler told Mr. Frank, Anne's father, that a building clerk named Carl could have found out about the Jews' hiding place and was therefore blackmailing him. This makes all Jews very sad and very afraid of being denounced.