Six African high school students who vanished from an international robotics fair in Washington remained missing — sort of — Sunday as investigators tried to determine where they are and whether their own families conspired in their disappearance.

The Burundi team attended the three-day FIRST Global Challenge that kicked off July 16. The event was supposed to be a celebration of global community and science, and it brought together competitors from more than 150 nations.

Burundi, an East African nation of 10 million people with a history of political and economic instability, was represented by a team of four boys and two girls, ages 16 to 18. The team's page on the First Global website talks about the teens' slogan, “Ugushaka Nugushobora,” which in their native Kirundi language loosely means 'Where there's a will, there's a way."

"We get our motivation for winning this competition through this slogan, which inspires Burundian team," according to the website.

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Ivanka Trump was among the celebrities to hang out with the competition's kids. President Trump personally had to intervene to ensure the team from Afghanistan got visas to attend. Everything went smoothly until the festivities wrapped up Tuesday night. That's when the Burundi mentor discover his team had left him their dorm room keys, packed their bags and disappeared into the hot, muggy Washington night.

"There were indications that the student's absence may have been self-initiated," First Global said in a statement. Still, the organization quickly notified local police early Wednesday, and the hunt was on.

By Thursday morning, police said two of the teens — Audrey Mwamikazi, 17, and Don Charu Ingabire, 16 — had been seen crossing into Canada. Police declined to say exactly where or exactly when, but added that there was no indication of foul play involving any of the disappearances.

No information was released on the fates of Richard Irakoze, 18, Kevin Sabumukiza, 17, Nice Munezero, 17 and Aristide Irambona, 18. On Sunday, police had little to add.

"There has been no further update at this time," police said in a statement to USA TODAY. "The investigation remains open."

The team's mentor, Canesius Bindaba, told The Washington Post he sent panicked messages to the teens' families back in Burundi after the kids disappeared. He said their replies made him suspicious — they suggested he relax, that everything would be OK.

FIRST Global President Joe Sestak said he was disappointed the students "chose not to return home" but added that he understood the challenges there. Bindaba agreed but said his tiny country suffers from “brain drain" as the best and brightest flee for better opportunities.

“For me, they were some kind of hope for the future of this project in Burundi,” Bindaba said. “It’s an opportunity for my entire country.”