Amit Soussana, an Israeli lawyer, was seized from her house on Oct. 7, beaten, and forced into Gaza by at least 10 men, some armed. Several days into her detention, she added, her guard began questioning her sexual life.

Ms. Soussana said she was detained alone in a child’s bedroom, shackled on her left ankle. Sometimes, the guard would enter, sit next to her on the bed, lift her shirt, and touch her, she alleged.

He also continually questioned when her menstruation was due. When her menstruation finished, around Oct. 18, she tried to put him off by pretending that she had been bleeding for nearly a week, she recalled. Around Oct. 24, the guard, who called himself Muhammad, attacked her, she alleged.

Early that morning, she said, Muhammad freed her chain and left her in the bathroom. After she undressed and began washing herself in the bathtub, Muhammad reappeared and stood in the doorway, clutching a revolver.

“He came towards me and shoved the gun at my forehead,” Ms. Soussana recalled during eight hours of interviews with The New York Times in mid-March. After beating Ms. Soussana and forcing her to remove her towel, Muhammad touched her, perched her on the edge of the bathtub, and hit her again, she claimed.

He carried her at gunpoint back to the child’s bedroom, a room adorned with images of the cartoon figure SpongeBob SquarePants, she recounted. “Then he, with the gun pointed at me, forced me to commit a sexual act on him,” Ms. Soussana added.

Ms. Soussana, 40, is the first Israeli to talk publicly about being sexually raped during captivity after the Hamas-led incursion on southern Israel. In her interviews with The Times, done primarily in English, she offered graphic descriptions of sexual and other assaults she faced during a 55-day ordeal.

Ms. Soussana’s personal narrative of her experience in captivity is consistent with what she told two doctors and a social worker less than 24 hours after she was freed on Nov. 30. Their accounts regarding her account indicate the nature of the sexual act; The Times agreed not to disclose the specifics.

Ms. Soussana recalled being kept at nearly half a dozen venues, including private homes, an office, and a subterranean tunnel. Later in her imprisonment, she alleged, a group of captors stretched her across the distance between two couches and pummeled her.

For months, Hamas and its sympathizers have denied that its militants sexually mistreated people in custody or during the Oct. 7 terrorist attack. This month, a United Nations report said that there was “clear and convincing information” that some hostages had suffered sexual violence and there were “reasonable grounds” to believe sexual violence occurred during the raid, while acknowledging the “challenges and limitations” of examining the issue.

After being released along with 105 other hostages after a cease-fire in late November, Ms. Soussana talked only in limited terms publicly about her treatment in the Gaza Strip, cautious of repeating such a horrific ordeal. When filmed by Hamas minutes before being liberated, she said, she feigned to have been treated properly to avoid risking her freedom.