The Israeli military says one of four bodies handed over by Hamas on Tuesday night, local time, is not that of an Israeli hostage.
The remains were taken to Israel's National Forensics Institute in Tel Aviv, where they had been undergoing examination and identification.
Three of the bodies have been identified as Uriel Baruch, Tamir Nimrodi and Eitan Levi.
The Israel Defense Forces now says the fourth body "does not match any of the hostages," adding that "Hamas is required to make all necessary efforts to return the deceased hostages".
Israel has been awaiting the return of the bodies of 28 dead hostages.
The bodies of another four hostages were returned to Israel on Monday, local time, when the last 20 living hostages in Gaza were released.
The handover of the four bodies on Tuesd