More: The grand jury's rejection of the felony charge was a remarkable failure by the U.S. attorney's office in Washington and the second time in recent days that a majority of grand jurors refused to vote to indict a person accused of felony assault on a federal agent. It also amounted to a sharp rebuke by a panel of ordinary citizens against the prosecutors assigned to bring charges against people arrested after President Trump's deployment of National Guard troops and federal agents to fight crime and patrol the city's streets.

The rejection by grand jurors was particularly noteworthy given the attention paid to the case of the man who threw the sandwich, Sean C. Dunn. Video of the episode went viral on social media, senior officials talked about the case, and the administration posted footage of a large group of heavily armed law enforcement officers going to Mr. Dunn's apartment.

It remained unclear if prosecutors planned to try again to obtain an indictment against Mr. Dunn, 37, a former Justice Department paralegal. They could also forgo seeking felony charges and refile his case as a misdemeanor, which does not require an indictment to move forward.