Legal provisions if girl suicides under mental torture and blackmail

A very common friend of mine is now in trouble the matter is like this Boy name:  , Girl friend name: 1) gave death threatening warning to his past girlfriend  who is married someone and  is also married,  keep calling to  and givening threatening to not upload her photo with his husband on facebook and blackmailing by saying he have her photos and videos 2) Now that  who is the mother of two committed suicide at 17aug 3) Police investigated that last incoming call on  was of  and police find some more audio calls from phone of  From this it proves that  committed suicide because the  blackmailing her so in these matters, I wants to know under which IPC act police can lodge and how many years of jail ones can get if the court found him guilty?