Baruch Dayan Ha'emes is the brachah associated with bad news. More specifically, it has become known as the brachah to say when hearing of the news of someone's passing.
Is it appropriate to say Baruch Dayan Ha'emes when someone commits suicide? On the one hand, someone Jewish died. On the other hand, the person who died killed someone, and their death was itself an act of retzichah.
From dinonline:
https://dinonline.org/2012/11/02/dayan-ha-emes-over-suicide/
One does not recite the “Baruch Dayan Ha-Emet” over a suicide. The reason for this is that the blessing refers to Divine judgment, which is part of His will. In the case of a suicide, death itself is a sin, and this is clearly not Hashem’s will, so that it is inappropriate to recite the blessing (see Yalkut Yosef 56:1).
This applies specifically to a suicide that is not mourned for, and not to somebody who took his life out of mental disturbance.
