1)How does he know Miss Brody Castillo? Why is she the main suspect?
Mr Van Leeuwen met Miss Castillo during a trip in Milan, he was here for business and she charmed him!
Miss Castillo is the main suspect because the police found her in the muder room with a gun.


2)Did Mr Van Leeuwen and Mrs Van Leeuwen have a troubled marriage?
Mr Van Leeuwen was not very present at home and it make Mrs Van Leeuwen sad....

3)Did anyone really want to kill Mr Van Leeuwen?
Nobody have not really conviction to kill him...And Mrs Van Leeuwen kill him because she was panic and desesperate!