The mother of Shani Louk, an Israeli-German woman thought to have been kidnapped by Hamas fighters at a music festival in Israel, says her daughter is dead.
Speaking to German media, Ricarda Louk said she had been told by the Israeli military that a DNA sample taken from part of a skull bone proved to be Shani's.
Her body has not yet been found.
Shani's sister also confirmed the death on social media.
Adi Louk wrote on Instagram on Monday that Shani had been killed in the "massacre at Re'im" - a reference to the attack staged by Hamas in southern Israel, near the Gaza Strip, on 7 October.
But it was not clear from the reports where or when the fragment of her skull had been found.
Israel's foreign ministry wrote on X, formerly Twitter, that it was "devastated" to have to share the news of her death.
The 22-year-old had been attending the festival near the Kibbutz Re'im when gunmen opened fire and sent terrified partygoers fleeing through the desert.
More than 260 people were killed, the Israeli authorities said, while others were taken hostage.
Soon after the attack, a video began circulating widely on social media, showing the body of a young woman being paraded through the streets in the back of a flatbed truck, surrounded by armed fighters and others yelling "Allahu Akbar" (God is Greatest).
The woman was lying face down but Ms Louk's family say they identified her from her dreadlocks and distinctive tattoos.