The district attorney in Uvalde, Texas, has said for months that she intended to convene a grand jury to consider evidence from the 2022 shooting at Robb Elementary School, with the possibility that state criminal charges could result over the botched police response to the massacre.

The district attorney, Christina Mitchell, said in an email in December that she would “dissect the investigation of the Texas Rangers” into the shooting “and then present same to an Uvalde County grand jury for review.”

On Friday, it emerged that selection for the grand jury had begun, according to a person familiar with the matter. The inquiry was likely to last months.

Word that the grand jury had begun to be convened, first reported by The Uvalde News-Leader, came a day after the Justice Department published a 600-page report that found broad and “unimaginable” failures that delayed the response and subsequent medical care to the victims after the mass shooting.