Can one make a Dayan HaEmet on a pigua, such as the one today in Israel, or is a personal connection to the victim(s) necessary?
The Bach (223) rules that no personal connection is required, and that those who only say “baruch Dayan Ha-Emes” are mistaken. This is also ruled by the Magen Avraham (223:4) and by the Mishnah Berurah (223:8), unlike the ruling of the Taz. The wording of the poskim is that if the person who died was an adam kasher, and a person feels personal anguish over his passing, he should recite the blessing.
Therefore, if a person feels pain and anguish over a pigua (as we should), in which Jews are tragically killed, it is right to recite Dayan Ha-Emes.