Hamas murdered Kfir (age 4) and Ariel Bibas (age ten months) in November 2023. They just returned the boys' bodies to Israel, but to increase their cruelty, the body they said was the boys' mother Shiri turned out not to be her, or any of the hostages.
https://www.timesofisrael.com/liveblog_entry/israel-said-to-lodge-protest-with-mediators-as-it-demands-hamas-free-shiri-bibas/