- Israel and Hamas agreed on a truce in exchange for the release of 69 hostages.
- Many are still in captivity, and Hamas is said to be unable to find about 40 of them.
- Six hostage-negotiation experts explained to Business Insider how this could happen.
As of Tuesday, 69 had been returned in exchange for a truce, and a release of detainees from Israeli prisons.
The ceasefire and exchanges could continue, so long as Hamas can keep supplying captives. But that may be difficult.
A mediator in the negotiations — Qatar's prime minister — told The Financial Times on Sunday that Hamas was unable to locate some 40 women and children being held.
Six experts on hostage-negotiation efforts, who spoke to Business Insider, explained how Hamas might have been able to allow hostages to go missing in Gaza.
Chaos and confusion
Scott Walker, a veteran hostage negotiator and former counter-terrorism advisor to the UN, highlighted the role of the "fog of war" in the possible disappearance of hostages.
"You've got to appreciate that there's lots of confusion, with the fact that Gaza is essentially a warzone," he told Business Insider.
Hamas rounded up a lot of hostages on October 7, and Gaza quickly found itself in a state of chaos amid Israeli retaliatory strikes.
More than 14,500 people in Gaza have died as a result of the strikes, according to the Hamas-run authorities.
"I think there's an assumption that there's some kind of seamless, coordinated response behind the scenes," he said. "But actually, let's think about the reality here. There's going to be lots of confusion, lots of uncertainty."
Hamas is not the only armed group in Gaza
Several experts suggested that Hamas may be unable to account for all of the hostages because they are being held by rival groups who might not want to strike a deal.
Brian Carter, the Salafi-Jihadi Team lead analyst at AEI's Critical Threats Project, told Business Insider: "Hamas may not know the whereabouts of hostages held by the al Aqsa Martyrs' Brigade, PIJ [Palestinian Islamic Jihad], and other, smaller groups."
The Palestinian Islamic Jihad, a rival group to Hamas, claimed in a statement posted by its ally, Lebanon's Hezbollah, that it had more than 30 of the hostages, around one eighth of the total.
It said it would not release them until all Palestinian prisoners held by Israel were released, according to The Wall Street Journal — a far bigger demand than Hamas has made.
Hans-Jakob Schindler, a senior director of the Counter Extremism Project non-profit, told BI that groups like the PIJ may seek to play the situation to its advantage.
"Hamas cannot just order those hostages to be handed over, especially since all of the others understand that the hostages could be very valuable for them as well," he said.
According to Schindler, Hamas is not only negotiating with Israel, but it is also dealing with "internal Palestinian negotiations" to recover hostages from other groups.
He added: "This is the most complex hostage situation I've seen ever, not just because of the number of hostages, but because of the number of groups that hold hostages, and those groups don't answer to Hamas."
A remote possibility of escapes and deaths
There's also a chance that some of the hostages may have escaped, been transferred to other groups, or died, according to Schindler.
"It is always possible that hostages can actually escape from wherever they are held," he said.
He pointed to reports about Roni Krivoy, a freed Israeli hostage, who is said to have briefly escaped his captors after the building he was in was bombed.
Schindler said that while it was possible some had died, he said Hamas would be unlikely to keep that secret, and would seek to blame the deaths on Israeli bombing.
Rachel Briggs, the CEO of The Clarity Factory security consulting group, was skeptical of Hamas claims not to be able to find people.
It could be claiming not to have the hostages to buy more time away from the fighting, she said.
"From the get-go, the way in which these releases have been orchestrated with a sort of drip-drip-drip over days, that certainly wouldn't have been Israel's preferred approach to this," she said.
She added: "So that to me suggests that playing for time is definitely something that Hamas is trying to do. "
Professor Boaz Ganor, President of Israel's Reichman University, who has previously advised the Israeli government on counterterrorism, told BI that he agreed with the buying-time thesis.
"The whole process of saying they don't know is for one purpose only and this is to stall," he said.
Ganor cited two possible reasons for this.
One, he said, was to drag out Israel's military campaign, hoping the passage of time would weaken its support from its allies.
"Every day that passes, the Israeli legitimacy declines," he said.
Another, he said, was for Hamas to regroup for when the fighting restarts.
"I tend to believe that we will see much harsher resistance from Hamas afterward," he said.
All of the above
For Chris White, the co-founder of Negotiation Global, who has experience of hostage negotiations in Gaza, hostages going missing could be plausibly explained by all of the above explanations.
He told Business Insider: "Is it possible that some hostages escaped? Yes. Is it possible that some have passed away? Yes. Is it possible that some have been sold on possibly to other groups by unscrupulous people? Yes. And is it possible that actually, it was so chaotic that Hamas doesn't actually know where they all are? Yes."
"All of the above are possible."