On 30 Nissan 5752, two yeshiva students, Yeshaya Cohen and Levi Endel, wrote to the Rebbe, King Moshiach, stating that the “Ezrat Achim” organization had invited them to Russia for several months. They sought the Rebbe’s approval and blessing to prepare local Jews and non-Jews for the imminent Redemption and to inform them that the Rebbe is Moshiach. They also expressed a wish for the Rebbe to reveal himself to the world as King Moshiach.
At 22:30, the Rebbe’s secretary, Rabbi Groner, called to inform them that the Rebbe approved all points of their letter, including informing everyone that the Rebbe is Moshiach.
It should be noted that in those years, emissaries in Russia were already telling people that the Rebbe is Moshiach, as evidenced by Rabbi Berel Lazar’s speech in 1993.