More info here:
Of note:
“Landeros, who identified by the non-gender-specific pronouns they/their/them, was divorced and shared joint custody of their two daughters with Landeros ex-wife. Landeros enrolled one of the daughters in the school several days before the incident without informing the ex-wife, Perlow said. Landeros ex-wife learned of this and brought custody paperwork to the school. The school called Timm, the school resource officer, following the districts practice of calling in law enforcement to mediate custody disputes. The school also called Landeros. Johns, another school resource officer, responded when Timm called for assistance.”