Yom Kippur, the Day of Atonement, is the holiest day in the Jewish calendar. That a murder would take place on Yom Kippur (or during the Days of Awe) runs opposite to Jewish belief. Let's hope murders only take place in fiction!
Here's a short updated list of Mysteries that take place on Rosh Hashana, the Days of Awe and/or Yom Kippur.
As always, I welcome any additions to this list.
Three Weeks in October by Yael Dayan
Days of Atonement by Michael Gregorio
Yom Kippur Murder by Lee Harris
A Guide for the Perplexed by Dara Horn
Day of Atonement by Faye Kellerman
Saturday the Rabbi Went Hungry by Harry Kemelman
The Day of Atonement by David Liss
A Possibility of Violence by D.A. Mishani
Nights of Awe by Harri Nykanen
Devil Among Us by Jack Winnick
Murder is no Mitzvah: Short Mysteries about Jewish Occasions
Mystery Midrash: An Anthology of Jewish Mystery & Detective Fiction, edited by Lawrence W. Raphael
Jewish Noir, edited by Kenneth Wishia
"The Lord is my Shamus" by Barb Goffman
May you be inscribed in the Book of Life for the coming year!