WASHINGTON — The big controversy leading up to the FIRST Global international robotics competition in Washington was whether a team of girls from Afghanistan would be able to participate, after their initial visa applications were denied.

As it turned out, the Afghan girls got into the country and competed without incident, though it took direct intervention from President Donald Trump. Instead, it was a team from Burundi that created an immigration-related uproar after it disappeared in what appears to be an effort to avoid returning to their home country.

The disappearance of the six Burundi teens from the competition is casting a spotlight on the visa process used to admit competitors.

D.C. police are continuing to investigate the disappearance, though they say there are no indications of foul play. Two of the six teens were seen crossing the border into Canada, police say. Event organizers believe the teens may have planned their disappearance, and members of the Burundi-American community say they have little doubt the teens are planning to seek asylum, either in the U.S. or in Canada.

Police reports indicate that the Burundi teens were in the country on travel visas valid for one year.

Just because the visa is valid for one year, though, doesn’t mean the teens are entitled to stay in the U.S. for a full year.

Betsy Lawrence, director of government relations for the American Immigration Lawyers Association, explained that they yearlong tourist visa for the Burundi teens are the result of negotiations between the U.S. and Burundi on the standard visa length.

But that’s only half of the equation. Once you obtain a visa, a traveler still must seek admission through Customs and Border Patrol agents at the arriving airport. The CBP agent will ask questions about the reasons for a traveler’s stay, and how long they expect to be in the U.S. CBP will then limit that person’s stay to a certain number of days or weeks. Overstaying the term imposed by CBP can result in enforcement action, Lawrence said.

William Cocks, spokesman for the State Department’s Division of Consular Affairs, said the State Department screens visa applications, and one of its goals is to ensure that visa applicants aren’t trying to use a tourist visa to permanently immigrate into the U.S.

He declined to discuss the Burundi teens’ specific situation.

Stephen Sapp, spokesman for Customs and Border Protection, also declined comment on the Burundi teens’ interaction with CBP.

It’s exceedingly rare for visitors or participants at international events like the robotics competition to disappear or use the event as a means to seek asylum, said Steven Schmader, president and CEO of the International Festival and Events Association in Boise, Idaho.

He said that when something like this occurs, “it does make everybody take more precautions. If something happens at one event in one year, then the next person, right or wrong, is going to have to go through a whole lot more hoops the next year.”

The robotics team’s coach, Canesius Bindaba, told The Washington Post that he had heard rumors the teens might be planning to stay in the United States. Speaking over WhatsApp from Kenya, a stop on his trip home, Bindaba said he hoped the rumors weren’t true.

“I just tried to build some kind of trust, hoping they were just rumors,” he said.

The competition, designed to encourage youths to pursue careers in math and science, attracted teams of teenagers from more than 150 nations. It had been in the national spotlight already, thanks to a team of girls from Afghanistan who were allowed to attend after President Donald Trump intervened on their behalf. Twice, their visas had been rejected — an Afghan official said the Americans feared they wouldn’t go home.

This combination of photos provided by the Washington Metropolitan Police Department shows six Burundi teenagers who were reported missing on July 19, 2017, after participating in an international robotics competition in Washington. The two girls and four boys ranging in age from 16 to 18 are, from top left, Richard Irakoze, Kevin Sabumukiza, Nice Munezero, and from bottom left, Aristide Irambona, Don Ingabire, and Audrey Mwamikazi. (Washington Metropolitan Police Department via AP)