suicide note and commit suicide after

Sir if a person (A) says “he will put someone’s name (B) in suicide note and commit suicide after that”. What will be legal value of suicide note ? Which type of Trail mentioned name person (b) will face? If before that issue we(A and B) were good friends. Now that person (A) says that (B) clues about (A) due to frighten off leakage of clues (A) commit Suicide. Please guide me