The Israeli police have begun an investigation and have so far gathered more than 1,500 testimonies.
Shari Mendes, a reservist who worked for two weeks at the base helping medics with fingerprinting and cleaning female soldiers' bodies at the Shura defence base, said many women who were killed that day were brought in while only in their underwear.
"I saw very bloody genitals on women,” she said.
One issue facing the investigation is that the women's clothes were buried with them before police investigators could examine them.
This is because, in Jewish burial law, the dead must be treated with dignity and laid to rest as soon as possible and everything that is a part of the body is buried together.
Another challenge is that there was a delay in Israeli soldiers being able to enter the sites where battles raged on for days – so opportunities were lost to gather perishable evidence to link violence to specific suspects.
Ms Mendes is one of at least seven first responders or others dealing with the dead that attest to alleged sexual violence in the past few days.
Those people said they found women semi-naked, bound, eviscerated, stripped, bruised, shot in the head or torched, at two communities including Kibbutz Beeri, and at an open-air music festival near the Gaza border fence.
Reuters news agency reviewed images matching some of the descriptions or attesting to other possible atrocities but it could not independently verify all the accounts.
Professor Ruth Halperin-Kaddari, who spent 12 years as a member of a UN convention on discrimination against women, told the BBC about videos she said left her in “no doubt” multiple women were raped.
She accused Hamas of using sexual violence as a war crime and repeated testimony from a survivor who said he saw a woman being gang-raped by several men while he hid in a bush.
"I saw footage and pictures from numerous locations of bodies whose condition were all exhibiting the same pattern of mutilation and leaving no doubt that rape was performed on these women before they were executed," Professor Halperin-Kaddari told BBC Radio 4's Today programme.
Hamas said it “categorically rejects the false allegations of rape propagated by the occupation, aimed at distorting the resistance and deflecting attention from the humane and ethical treatment accorded to released detainees”.
The militant group went on to criticise the media for reporting the accusations.
Taher al-Nono, the media adviser to the head of the political bureau of Hamas, denied Hamas fighters were responsible for any sexual assaults in the attack and called for "a serious and impartial international investigation into the matter".
A United Nations commission of inquiry investigating war crimes on both sides of the Israel-Hamas conflict will focus on allegations of sexual violence by Hamas in the October 7 attacks.
But Israel accuses the commission of bias and has said it will not cooperate with the investigation.
The UN has faced criticism for not saying anything about the allegations until November 25, when it posted on social media that it was “alarmed by reports of gender-based violence on 7 October and calls for rigorous investigation, prioritising the rights, needs and safety of those affected”.
“This took them too long, much too long,” Professor Halperin-Kaddari said.
The Rome Statute of the International Criminal Court, in force since July 2002, includes “rape, sexual slavery, enforced prostitution, forced pregnancy, enforced sterilization, or “any other form of sexual violence of comparable gravity as a crime against humanity when it is committed in a widespread or systematic way”.
There are several requirements for attacks to be considered weapons of war and this includes when it can be proven there was an explicit intention to use it as a military strategy and when instructions to use it have been given by higher-ups.
Israel does not recognise the ICC’s jurisdiction but Israeli individuals and the state itself are free to submit evidence.
Tel Aviv-based lawyer Yael Vias Gvirsman is gathering evidence for families of 54 victims which will include victims of sexual and gender-based violence, to present to the ICC.
She said: "That brings us to sort of, I'll call it the Israeli dilemma, referring to where such cases could be judged.
Israel may hold some perpetrators but does not have the reach of the instigators, commanders or aiders and abetters that the ICC could bring to trial, she said.
She and another attorney expect the Israeli government eventually to turn to the ICC. Israel's Justice Ministry declined to comment on this speculation.