A panel of international experts investigating the 2014 abduction of 43 students in southern Mexico said on Tuesday that it was ending its inquiry after being repeatedly lied to and misled by the Mexican armed forces about their role in the crime.

Members of the Mexican military misrepresented their whereabouts during the crime, denied access to key documents and withheld details about their involvement in the disappearance and its subsequent cover-up, the experts said in a report released on Tuesday, their sixth and final assessment of a notorious event that remains shrouded in mystery.

“It hurts to see how a case that could have been solved in the first few weeks ended up entangled in lies, falsehoods and diversions of the investigation,” the report said.

In a news conference in Mexico City on Tuesday, the panel members — appointed by the Inter-American Commission on Human Rights in 2014 — cited their frustration at the armed forces’ unwillingness to cooperate.

“It’s all lies, one after another,” Carlos Beristain, a Spanish doctor and panel member, told The New York Times on Monday night. “We’re not going to stay if we don’t have a chance to get answers,” he added.

The panel arrived in Mexico in 2015 and its work was key to discrediting an earlier version of events deemed fabricated by the administration of former President Enrique Peña Nieto, known as “the historical truth,” which blamed only local police officials and organized crime for the disappearance.

More recently, only two members of the panel remained on the committee and its mandate had expired.

The independent panel’s latest findings include a new technical analysis of cellphone data and documents that placed several members of the military at locations connected to the attack while it was underway, in places and times they had never mentioned in their testimonies.

What they were doing exactly is unclear. “What we do know is that the story told is not true,” said Dr. Beristain.

The technical analysis revealed a constant flow of communications that reached the top levels of the military in the region. Mexican soldiers not only knew about but most likely witnessed the shootings, the detentions and the violence “second by second,” Ángela Buitrago, a Colombian lawyer and another panel investigator, said during the news conference.

“What all the technical information shows is the lie in many of the statements” provided by the military, added Dr. Beristain. “They say they were not in places where they were.”

Previous committee reports said that the army had real-time knowledge about the attack, did not share that information with the authorities and then deliberately obstructed the investigation.

The investigators also obtained a confidential document from the navy indicating that two people had died while detained by the marines. A photograph of the bodies showed the men had their hands tied with a cloth “similar to those seen in videos of arrests made by the navy,” the report said.

In 2018, the United Nations Human Rights Office reported that another person tied to the crime had died while in the marines’ custody as a result of being tortured.

The 43 students disappeared in the rural state of Guerrero in September 2014, after hijacking several buses to attend a march in Mexico City — a practice mostly tolerated at the time.

That night was different.

Local police officers and other gunmen opened fire on the students, and by daybreak, six people had been killed and dozens of others wounded. The students were never seen again. The remains of only three bodies have been identified.

President Andrés Manuel López Obrador of Mexico vowed to solve the case and bring closure to the families — a pledge he campaigned on in 2018. But despite the recent arrest of a general and 15 soldiers in connection to the disappearance, the government has yet to secure a single conviction.

On Tuesday morning, Mr. López Obrador said he had met with the independent experts the day before and thanked them for their work. “We will continue with the investigation,” the president said. “I have the commitment to get to know the whole truth.”

The latest report found that, in October 2014, the marines illegally searched a river where the Mexican authorities had claimed to have found a bag with a bone fragment from one of the disappeared students. But, according to the report, the marines never disclosed that they had located the bag a day earlier. They had also found at least nine others; it’s unclear what happened to them.

“There are findings that were never documented, there were bags that were never reported,” the report said.

The committee’s final report “is a foot in the door to keep the door from closing,” said Dr. Beristain, adding that the end of the investigation does not mean the case is solved.

“There are many things left to do,” he said.