A day after a Malaysia Airlines jetliner was shot down and exploded over eastern Ukraine, the identities of the 298 people onboard who died are slowly being revealed.

Among the victims aboard Flight 17 were infants, dozens of AIDS research experts and the stepdaughter of a woman who also lost her brother aboard the still missing Malaysia Airlines Flight 370.

Australian native Kaylene Mann, who lost her brother Rod Burrows on Flight 370 after it vanished in March, now has to mourn the loss of her stepdaughter Maree Rizk, the Associated Press reported. Mann found out on Friday that Rizk was on the Kuala Lumpur-bound plane when it was shot down Thursday in an area of Ukraine controlled by pro-Russian separatists.

"It's just brought everyone, everything back," Greg Burrows, Mann's other brother, told the AP. "It's just...ripped our guts again."

Investigators believe Flight 370 crashed somewhere in the southern Indian ocean after taking off from Kuala Lumpur on March 8 with 239 people onboard. Now another tragedy has struck the same airline, also involving a Boeing 777 that was headed for Kuala Lumpur.

Burrows said they cannot wrap their heads around how their family could suffer from two mass-casualty airplane incidents.

"She just lost a brother and now a stepdaughter, so..." Burrows told the AP, unable to finish his sentence.

Officials from the International Aids Society confirmed it lost several colleagues aboard Flight 17, including the society's former president Joep Lange, NBC News reported. Glenn Thomas, a British spokesman for the World Health Organization, was also supposed to be on the plane, officials told the station.

"The International AIDS Society today expresses its sincere sadness at receiving news that a number of colleagues and friends en route to attend the 20th International AIDS Conference taking place in Melbourne, Australia, were onboard the Malaysia Airlines MH17 flight that has crashed over Ukraine earlier today," the society said Thursday.

U.S. intelligence officials said Flight 17 was struck by a surface-to-air missile before it crashed in Ukraine's eastern Donetsk region. The New York Times reported Ukraine's intelligence agency obtained phone recordings suggesting the plane was downed by pro-Russian separatists in the region. The investigation into those reports is ongoing.