REHOVOT, Israel — Yehuda Cohen has seen videos of the bloodstained tunnel where the bodies of six hostages were discovered last month. He fears conditions are deteriorating for his son, 20-year-old Nimrod, believed to be held somewhere in the labyrinth underneath Gaza. And he knows that every day of fighting heightens the risk of a similar tragedy.

       “There is a rope hanging over my son’s head,” said Yehuda, a 54-year-old algorithms engineer. “But we still have a reason to fight. I don’t think of anything else.”

       Yehuda Cohen and his wife, Viki, are clear: Hamas is a terrorist organization over which they have no control. Governments are supposed to protect their people. So the person controlling the rope, they say, is Prime Minister Benjamin Netanyahu.

       In the weeks since the bodies of the six hostages were found in Gaza — shortly after being shot at close range by their Hamas captors, Israel’s Health Ministry said — Israelis have returned to the streets for increasingly massive protests, calling on Netanyahu to secure the release of the remaining captives. But U.S.-backed cease-fire talks have faltered again, as Netanyahu insists on keeping Israeli troops along the Gaza-Egypt border and Hamas demands that more Palestinians be released from Israeli prisons.

       A spokesman for Netanyahu declined to comment for this story. In a recorded video message this month, Netanyahu blamed Hamas for failing to reach a cease-fire agreement and said efforts to free the hostages are ongoing. He also reiterated the importance of having troops along Gaza’s southern border, known as the Philadelphi Corridor.

       Among hostage families, the deaths of the six marked a turning point. Many who had been keeping their protests in Tel Aviv largely apolitical have now joined the more overtly anti-government demonstrations a few blocks away. The result, organizers say, has been the biggest crowds yet, measuring in the hundreds of thousands.

       “We are marching with one voice now,” said Lee Siegel, 72, whose younger brother, Keith Siegel, is still being held by Hamas. “When you are shooting, anything could happen. We know that war and hostages returning home do not happen together.”

       Every day, the Cohens try to keep up the pressure. Weekly, sometimes nightly, they protest. Last month, Yehuda and his older son, Yotam, traveled to Washington to plead with U.S. officials to force Netanyahu into a deal. They plan to return this month, with Viki and Nimrod’s twin sister, Romi, to make another push.

       “We have a chance to reconstitute our family … to put things back together, by bringing Nimrod home,” Yehuda said. “Any good parent would never give up on his child.”

       The Cohens were awakened by sirens at 6:30 a.m. on Oct. 7. Hamas-led militants had streamed out of Gaza to attack Israeli communities. They headed to the basement shelter of their plant-filled house in Rehovot, about 10 miles south of Tel Aviv. Yehuda rushed Yotam, then in the Israel Defense Forces, to his posting.

       Details of the attack were slow to emerge. Ultimately, it became clear that Hamas had killed about 1,200 people and dragged more than 250 back to Gaza as hostages.

       The Cohens did not immediately think of Nimrod, an IDF soldier with a tank unit stationed near Gaza.

       When Yehuda texted Nimrod at 9:30 a.m., there was no reply. When he logged on to YouTube, one of the first videos he saw was of a tank going up in smoke and soldiers being dragged out. His son was one of them.

       Nimrod, who enjoyed video games and solving his Rubik’s Cube, was often the peacemaker between his siblings, his parents said. He had deployed just two months before the attack.

       At first, the Cohens believed fighting might bring their son home. But that hope dissipated as they watched Israel’s military campaign grind on, killing tens of thousands of Palestinians and bringing Nimrod no closer to freedom.

       There are still 97 hostages held by Hamas in Gaza who were taken on Oct. 7, the Israeli government says; only 64 are believed to be alive.

       The Cohens say Netanyahu is prolonging the war for political purposes, catering to those in his far-right base who saw Oct. 7 as an opportunity for Israel to reoccupy Gaza. They were appalled, but not surprised, when they heard a rabbi in the IDF declare the first month of war the “happiest of my life.” The Israeli military disavowed the rabbi’s comments.

       “They make the land sacred instead of the lives of people,” Viki said. “That is why we are in the situation we are now.”

       In Washington, the Cohens will push U.S. officials to use whatever leverage they have against Netanyahu — even suspending the sale of weapons or ammunition to Israel, they said, if that’s what it takes to bring the hostages home.

       In Tel Aviv last week, Yehuda and Einav Zangauker, a onetime Netanyahu supporter who became one of his most vocal critics after her son was kidnapped, led a small but determined weeknight crowd in chants calling for an end to the war. They brandished signs with faces of hostages and posters demanding the government “SEAL THE DEAL.” They blocked traffic, they said, to remind people in the bustling city that life cannot go on as normal.

       Some in the crowd expressed a feeling verging on hopelessness. After so many months on the streets, demonstrators said, they doubted the protests had much effect, but they kept coming to support the families.

       “We are stuck,” 74-year-old Nili Granot said. “The decision is between Netanyahu’s ears.”

       When Lee Siegel learned of the six slain hostages, he thought of the families of Israeli American Hersh Goldberg-Polin, 23, and Carmel Gat, 40. Since Oct. 7, they had become like his own family. Then he thought of his brother, who was taken from Kibbutz Kfar Aza on Oct. 7. He wondered if he had been killed but not yet discovered.

       “There is a feeling of desperation, of things being out of control,” Siegel said. “A feeling of ‘What can we do?’ But then we come back to: We have to hope. And we can’t be silent.”

       Yehuda was protesting here last month when another family member of a hostage said there were rumors that bodies had been found in Gaza. Yehuda called Yotam, who quickly found the names of the dead on Telegram. Yehuda asked the man whether he wanted to see the list, explaining that it concerned his relative.

       “His whole face just fell,” Yehuda said. “It is impossible to describe.”

       Viki Cohen misses the everyday things most. The mess of clothing on Nimrod’s floor. How he would leave just the tiniest bit of ice cream in the carton. His laugh.

       Yehuda said he can envision his son returning home “like a Hollywood movie” — all of their efforts paying off, the family again complete. He tries not to let himself think about the alternative.

       When Nimrod comes back, the Cohens said, he’ll need help processing the trauma of being in captivity for so long. One reason they speak to reporters, Yehuda said, is a hope that Nimrod will see them on television or the internet, and that it might boost his spirits.

       “Because we hope,” he said, and paused briefly. “I would say I am sure — but I am very realistic, so I say hope — that it will end before he will be murdered, and he will be back with us.”