The Mishnah teaches us that the mothers of the High Priest would provide accidental murderers gifts and food so that they do not pray for the death of the High Priest which would allow them to go free from the Cities of Refuge.

The Sages of the Land of Israel teach us that if the Gates of Prayer just happen to be open ill wishes may automatically come true. Makkoth 7b

One should never wish another Jew ill because there is the chance that these wishes may come true even if the accusations are completely invalid and an innocent person may get punished.