The Honduran politician Juan Antonio “Tony” Hernández has been found guilty in a vast drug conspiracy case in New York City after prosecutors said he relied on “state-sponsored drug trafficking” enabled by his brother – the country’s president.

“Tony” Hernández was impassive as the verdict was announced by a jury that deliberated over parts of two days. He was convicted of drug conspiracy, weapons charges and lying to the Drug Enforcement Administration.

The two-week trial put a spotlight on the lucrative drug trade between the United States and Honduras, where poverty, violence and corruption have driven thousands of migrants to flee north through Mexico.

US prosecutors say the drug conspiracy was protected by the Central American country’s government. The trial featured testimony that the convicted Mexican drug lord Joaquin “El Chapo” Guzmán gave $1m in bribes to Antonio Hernández to pass along to his brother.

The defense lawyer Michael Tein had argued that prosecutors had insufficient evidence and that five turncoat witnesses who admitted to dozens of killings were “liars, losers and murderers”.

The Honduran president was not charged in the case but was labeled a co-conspirator. The president tweeted during the trial that the prosecution’s allegations were “100% false, absurd and ridiculous”.

Juan Orlando Hernández speaks during a rally in his brother’s support in Tegucigalpa, Honduras, on 9 October. Photograph: Jorge Cabrera/Reuters

In a closing argument Wednesday, the assistant US attorney Emil Bove said the drug conspiracy was already over six years old in 2010 when Antonio Hernández and his associates gained control of the government to protect drug traffickers aligned with the country’s National party.

“That is state-sponsored drug trafficking. And with that level of power and control, the defendant was virtually untouchable,” he said. “The results of that are astonishing.

“Beginning in 2010, the defendant worked on massive cocaine shipments sent to the United States on a monthly basis. The president of Honduras deployed the military to the border with Guatemala to protect the defendant’s drug turf. The defendant used the national police to murder one of his drug rivals. And the ringleader in that murder was later promoted to become the chief of the entire police force,” Bove said.

Meanwhile, the prosecutor said, Guzmán was able to travel to Honduras in 2013 twice despite being one of the most wanted people in the world.

“And during the second meeting, he handed the defendant a million dollars in cash, drug money, to help the defendant’s brother, Juan Orlando, get elected president so he could keep protecting them,” the prosecutor said.

Juan Orlando Hernández has been seen as a key regional ally by Washington, which was quick to recognize his re-election in December despite widespread allegations of fraud. Last month, Honduras agreed to allow the US to return asylum seekers from third countries to the violence-stricken Central American nation.