A congruence relation satisfied by Igusa's cusp form of weight~35 is presented. As a tool to confirm the congruence relation, a Sturm-type theorem for the case of odd-weight Siegel modular forms of degree~2 is included.
"Note on Igusa's cusp form of weight 35." Rocky Mountain J. Math. 45 (3) 963 - 972, 2015. https://doi.org/10.1216/RMJ-2015-45-3-963