In HaYom Yom, 12 Teves the Rebbe informs us that in 1887 the Rebbe Rashab was elected as a gabbai (an official) of the Chevra Kadisha. As was customary he was led on Simchas Torah in procession to the shul accompanied by a throng. He then said a Ma’amar beginning with the words, Ein HaKodosh Boruch Hu Ba Bitrunya.
In Sefer HaSichos 1936, p. 165 he adds that after the Ma’amar a group of simple yidden approached the Rebbe and exclaimed, “Gabbai! If you will give the command, we will even go into fire!” “Yes,” the Rebbe replied, “one must go into fire! One must recite Tehillim with fire (mit ah bren).”
Rabbi Mordechai Perlow, in his sefer Likuttei Sippurim (p. 194) adds that towards the Rashab’s last years in Lubavitch, 1914-1915, he was involved in local community matters and was appointed gabai of the Chevra Kadisha. When he had to leave Lubavitch he appointed Reb Shlomo Chaim Kiton the local shochet as his replacement for Chevra Kadisha matters.