One source with knowledge of the talks, which slowed after the Israeli ground invasion, said a central point of discussion was a demand by the Israeli side for Hamas to provide a full list specifying the name and details of each person held in Gaza. The Israeli side was unwilling to cease bombardments without receiving this list.

Hamas responded that it was unable to provide the list without a pause in the fighting, as the estimated 240 hostages were held by a number of different groups in places across Gaza. That suggested even Hamas leaders do not know for sure how many people are held captive, their locations or the number who have survived the bombardments.

There's a lot of conflicting information from the sources in this story though.