They said that the president used drug money to help win elections in 2013 and 2017, and that he offered protection to drug traffickers who supported him. They said President Hernández also considered eliminating a Honduran law that allowed for the extradition of traffickers — a law that he had himself pushed through Congress when he led that body — because he feared the United States would try to extradite his brother, the court filing shows.

President Hernández has not been charged in the case, and prosecutors do not use his name in court papers, labeling him only as CC-4, for co-conspirator No. 4. But they leave no doubt about his identity: “CC-4 was elected President of Honduras in late 2013,” the prosecutors wrote.

After the allegations became public in the court filing last month, protesters in Honduras, where the president is increasingly unpopular, renewed their call for his resignation, with many adding CC-4 alongside the president’s initials — J.O.H. — to the signs that appear at every rally calling on him to resign.

President Hernández, 50, has vigorously denied any involvement in the drug crimes.

As the date of the trial approached, President Hernández offered television interviews, asserting that his conscience was clear. The allegations, he told one interviewer last week, were made by people seeking favorable treatment from the court. Their statements, he said, “don’t have the slightest value, and that will be demonstrated in a trial.”

He blamed the allegations against him on revenge by traffickers who oppose his strong antidrug policies.