Stephanie Shults posted this photograph to her Facebook page in May, showing her with her husband, Justin, in Belgium. (Reuters)

This story has been updated.

Stephanie and Justin Shults, an American couple living in Brussels who had been missing since the attacks in the Belgian capital, were declared dead on Saturday, according to members of Justin Shults’s family.

“We found out today that cowards took my brother’s life,” Shults’s brother, Levi Sutton, posted on his Twitter profile. In another posting, he wrote: “The world lost two amazing people today. It’s not fair.”

Relatives and friends of Justin Shults also posted memorials and notices of the couple’s death on the Facebook page of his mother, Sheila Shell.

The Shultses never planned on living abroad, but when the chance to move to Brussels fell in their lap two years ago, they decided to embrace the spirit of adventure and go.

On Tuesday morning, the pair were at the airport, dropping off Stephanie’s mother, Carolyn Moore, to catch a flight home to Kentucky after a week’s visit. They parked the car, walked her into the terminal to get her boarding pass, said goodbye and walked away, according to Moore’s sister and Stephanie’s aunt, Betty Gragg Newsom. Then the first blasts of coordinated terrorist attacks in Brussels by the Islamic State ripped through the airport’s departure hall.

The couple’s car was found, Sutton posted on Twitter Saturday, but the family continued to wait without word about the couple, as they had for several days.

There was much the family didn’t know about what the Shults couple did after they parted ways with Moore. If they exited the airport to retrieve their car, they might have been far enough from the explosions to be injured but alive. If they opted instead to wait and watch Moore’s flight take off, they could have been much closer to the deadly blasts.

Newsom wasn’t sure where Moore was during the explosions, save that she had not yet gone through airport security. But the force of the blasts knocked Moore off her feet and left her with strange, dusty substances in her hair and without hearing in one ear, Newsom said.

Moore was taken to a nearby hotel, and was later joined in Brussels by her husband, Geary Moore. Shell, Justin’s mother, also traveled to the Belgian capital, to find out what happened to the couple.

On Friday morning, State Department officials said that at least two Americans had been confirmed dead in the blasts without listing their identities — raising speculation that Stephanie and Justin, the only American citizens to have been identified in the news media, might be among the deceased. But as the day wore on, it appeared that the announcement also could be referring to Alexander Pinczowski, 29, and Sascha Pinczowski, 28, Dutch nationals who lived in New York.

But all involved had already ridden out a heartbreaking moment of dashed hope, after some of Justin’s family reported receiving information that the couple had been found alive.

Information is trickling in about the victims of the Brussels bombings that killed at least 31 people on March 22 . Here’s what we know, so far, about the victims with U.S. ties. (Claritza Jimenez/The Washington Post)

On Wednesday afternoon, Sutton took to his Twitter account to announce that an official from the State Department had contacted his mother to tell her that the Shultses had been found. The news spread quickly — even the mayor of Lexington, Ky., Stephanie’s hometown, joined in the online cheering.

But it was confusing for Stephanie’s relatives, who had been in regular touch with officials and hadn’t heard anything. It soon became clear that the celebration was premature, and that Justin and Stephanie were still missing.

Sutton apologized later Wednesday via his Twitter account, saying he was “disgusted” that his family had received bad information and explaining that an official social worker helping Carolyn Moore in Belgium had helped straighten things out.

On Thursday, State Department spokesman Mark C. Toner told reporters that “we certainly apologize for any misunderstanding,” but he would not confirm that any department officials had contacted Shell or told her that her son had been found.

“They’re seeking information; we’re trying to respond and get them accurate information,” Toner said. “It’s incumbent on us to really try to get accurate information, and we just, we don’t have that yet . . . as soon as we have accurate information, we’ll obviously be back in touch with those families.”

Stephanie Shults’s relatives also want the mystery cleared up.

“We’re just trying to find out who she had gotten her information from,” Betty Gragg Newsom said of Justin’s mother. She took a deep breath before adding, “It was a little frustrating.”

Stephanie Moore, from Lexington in the heart of bluegrass country, and Justin Shults, from the mountain town of Gatlinburg, Tenn., met in graduate school while they were studying for master’s degrees in accounting at Vanderbilt University, where Justin had received a bachelor’s degree in economics in 2008. Both were remarkably bright, Newsom said. They married two years after graduation, in 2011.

Stephanie worked for the Mars company, in its pet-food division, and Justin for Clarcor, which makes filtration systems. They were based in Nashville, but they headed for Europe after Stephanie, who had majored in business and French at Transylvania University in Lexington, was offered a three-year position in Brussels by her company, Newsom said. Justin’s company let him make the move, too, in order to handle its international business accounts.

In Brussels the Shultses lived near the center of town, Newsom said, and they weren’t scared even as the Belgian capital began to gain a reputation as a hub for terrorist activity in Europe in recent months.

“They’ve just really enjoyed the experience of being in Europe,” Newsom said. “They had not mentioned feeling unsafe at all.”

Whenever they weren’t working, Newsom said, they traveled — to the running of the bulls in Spain, to London, to Paris, to Germany and other parts of Europe. They had been enjoying “the 30-something lifestyle before they have children,” Newsom said.

Justin Shults turned 30 this month, while Stephanie’s 30th birthday is in September.

Moore, who is retired, had made a few trips to Brussels to visit the couple and was squeezing one more in before the expected birth of her first grandchild — Stephanie’s older sister is due to have a baby soon.