A young American couple who quit their jobs and embarked on an around-the-world bicycle tour to demonstrate "evil is a make-believe concept" were killed in an ISIS-claimed terrorist attack.

Jay Austin and Lauren Geoghegan, both 29, left office jobs in Washington, D.C., having, according to Austin, "grown tired of spending the best hours of my day in front of a glowing rectangle," Pluralist.com reported.

Austin worked for the U.S. Department of Housing and Urban Development while Geoghegan worked in the Georgetown University admissions office.

They documented their year-long journey on Instagram and on a joint blog, sharing, the New York Times said, "the openheartedness they wanted to embody and the acts of kindness reciprocated by strangers."

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"You read the papers and you're led to believe that the world is a big, scary place," Austin wrote. "People, the narrative goes, are not to be trusted. People are bad. People are evil.

"I don't buy it," he said. "Evil is a make-believe concept we've invented to deal with the complexities of fellow humans holding values and beliefs and perspectives different than our own."

Their trip came to a horrific end, however, on July 29 when they were riding in the countryside in Tajikistan, a country with a known terrorist threat.

A car rammed them, CBS News reported, five men got out and stabbed the couple to death along with two other cyclists.

ISIS, two days later, released a video showing the five men sitting in front of the ISIS black flag, the New York Times reported.

The men, looking at the camera, vowed to kill "disbelievers."