They exchanged text messages and emojis. Brief status updates with words of encouragement. A picture of the beloved family dog "Tutsi."

Until no more messages came.

And then, Cindy Flash, an American, and her Israeli husband Igal vanished into the violence, presumed kidnapped by Hamas.

Four days after Hamas attacked Israel, more than 100 Israelis and potentially dozens of foreign nationals are thought to be held captive in the Gaza Strip. At least 14 U.S. citizens have been killed and an unknown number are still unaccounted for.

Flash, 67, originally from St. Paul, Minnesota, is one of them. She lives in Kfar Aza, a kibbutz in southern Israel near Gaza, where some of the most harrowing and grisly stories have been emerging during the last few days.

"They are breaking down the safe room door," Flash said in one of her final messages to her daughter Keren, 34. "We need someone to come by the house right now." She had been communicating with her parents from a few houses away.

Keren described her mother, who worked as an administrator in a local college, as someone who had the "sweetest biggest heart," who everyone knew and loved, and who had spent a lifetime advocating for the rights of Palestinians, including those who live in Gaza where she may now be held.