Judge Hellerstein died on Wednesday morning, according to a court spokesman. He was appointed in 1998 and was overseeing the trial of Nicolás Maduro of Venezuela.
More than a dozen news organizations have asked a federal judge to unseal documents related to a search warrant executed at Ms. Omar’s home this month.
In the legal tangle between the Justice Department and California, a federal judge on Tuesday deferred a ruling but said the government already had a remedy it could use after the election.