The crushing story behind the photo that shook the world.

The father cradled his nine-month-old twins, Aya and Ahmed, each in an arm. He stroked their hair and choked back tears, mumbling, “Say goodbye, baby, say goodbye” to their lifeless bodies.

Abdel Hameed Alyousef lost his twins, his wife and other relatives in the suspected chemical attack on Tuesday in the northern Syrian town of Khan Sheikhoun that killed at least 72 people.

In footage shared with The Associated Press, Alyousef sits in the front seat of a van with the twins, his eyes red as he asks his cousin Alaa to video his farewell to them.

Abdul Hamid Youssef losed 20 martyrs from his family at the chemical massacre including his wife and his twin children Ahmed and Aiya pic.twitter.com/jBu6Qeqpgn

— Asaad Hanna (@AsaadHannaa) April 5, 2017

When the airstrike took place, “I was right beside them and I carried them outside the house with their mother,”said Alyousef, a 29-year-old shopowner.

“They were conscious at first, but 10 minutes later we could smell the odour.”

The twins and his wife, Dalal Ahmed, fell sick. He brought them to paramedics and, thinking they would be OK, went to look for the rest of his family.

He found the bodies of two of his brothers, two nephews and a niece, as well as neighbours and friends.

“I couldn’t save anyone, they’re all dead now,” he said. Only later was he told his children and wife had died.

“Abdel Hameed is in very bad shape,” his cousin Alaa said. He’s being treated for exposure to the toxin, “but he’s especially broken down over his massive loss.”