In the days after 9/11, American attorney Gary Osen’s neighbor lost her husband in the World Trade Center attack. She was overwhelmed, caring for two small children and drowning in paperwork.
Osen stepped in to help—not just with funeral arrangements, but eventually with something far more consequential: a legal path toward justice for terrorism victims.
What began as a simple act of kindness would lead to a decades-long mission to hold those who fund terrorism financially accountable, from foreign banks to sovereign states.
Today, Osen and his law firm, Osen LLC, stand at the forefront of litigation in a specialized field—suing institutions, countries, and banks that provide financial support to terrorist organizations. His work, often under the radar and rarely celebrated by governments, has led to landmark legal decisions and groundbreaking accountability.
Osen LLC’s most recent major case (together with three other firms) was filed in D.C. federal court in April, on behalf of about 200 American family members of the October 7 victims. The suit accuses Palestinian-American billionaire Bashar Masri of knowingly working with Hamas in developing business properties in Gaza that concealed and provided electricity to the terrorist group’s elaborate, militarized tunnel network.
Osen’s foray into anti-terror litigation wasn’t planned. In the early 2000s, he was approached by the same 9/11 family he had helped. They wanted to know whether they could take part in litigation being filed against Saudi individuals and institutions suspected of financing Al-Qaeda. As Osen began researching, he uncovered a pattern: while Al-Qaeda’s funding routes were largely clandestine, support for Palestinian terrorist groups like Hamas was brazenly public.
In April 2002, for example, Saudi television aired a telethon to raise funds for the Second Intifada, which PLO leader Yasser Arafat had launched in September 2000, when Palestinian statehood seemed to be within touching distance.
The money was directed through a Saudi committee and distributed via Arab Bank, then the largest financial institution operating in the Palestinian territories. The bank even placed newspaper ads instructing families of suicide bombers which branches to visit to collect U.S. dollar payments—actions that fit squarely within the U.S. legal definition of providing “material support to terrorism.”
Osen began pulling at this thread, uncovering terrorism’s financial infrastructure with a litigator’s precision and a moral clarity drawn from personal loss and field experience.
Legal battles and setbacks
Though the U.S. Anti-Terrorism Act was passed in 1996, the Department of Justice has prosecuted just one corporation under it. Most terrorism-related civil litigation is driven by private attorneys like Osen. He and his team have represented hundreds of plaintiffs, including in the high-profile Arab Bank case, where his firm represented 40% of the 500 victims.
But the road to justice is long and uncertain. Cases against banks like NatWest and Crédit Lyonnais have been dismissed. Appeals drag on for years. Courts often exhibit institutional reluctance toward terrorism cases, preferring to view them as matters of state, rather than civil liability.
“There’s an unconscious institutional bias,” Osen explains. “Analytically, judges don’t like it; they feel like we’re stepping into roles that should belong to the government. It’s hard for them to accept that a private citizen can sue a bank for terrorism.”
Despite the resistance, the firm presses on, “litigating as hard as possible”—sometimes winning judgments against Iran, sometimes facing disappointment when banks escape liability.
Giving victims a voice
For survivors and victims’ families, Osen’s work is more than legal advocacy—it’s a way to fight back.
Eitan and Varda Morrell, parents of Maoz, who was critically wounded while serving in the Israel Defense Forces (IDF) in Gaza and succumbed to his wounds in February 2024, exemplify this. “A friend of my wife’s brother put us in touch with Osen,” said Eitan Morell, “he thought it was important to go after the people who finance the terrorism, and he wanted to connect us to the right lawyer.”
Like many surviving family members, he was surprised to learn he had a case, although he didn’t initially understand how. “Having had the whole process explained to me, the importance of holding financial institutions in the West accountable became clearer, more than in a few years, maybe seeing some money [in restitution].”
“This war globally is being fought on different fronts; the financial backing is one of the important ones. This is a fight of necessity,” Morrell added.
The impact of these cases extends beyond the courtroom. They provide families shattered by terrorism a platform to be heard, and they force the financial world to reckon with the consequences of ignoring the downstream effects of their services.
Sarri Singer never expected her life to become entangled in such a case. In 2003, she boarded a No. 14 bus in Jerusalem, becoming the victim of a Hamas suicide bombing. The attack killed 17 people and wounded more than 100.
Singer, then 29, survived with serious injuries. But the experience transformed her life’s trajectory. She became an advocate for terrorism victims and founded Strength to Strength, a nonprofit that connects and supports survivors of terrorism around the world.
Singer’s testimony has featured prominently in litigation brought by Osen’s firm. “I speak not just for myself, but for those who can’t speak anymore,” she said. Her voice and those of other survivors add a human dimension to cases often dominated by spreadsheets, SWIFT codes, and expert witness depositions.
She said that as the daughter of the prominent New Jersey State Senator Robert Singer, lawyers, unbidden, quickly inundated her with offers of assistance and potential help with litigation while recovering from her wounds. No, she would take her time and make a move when she was good and ready.
It took three years, and to that extent, Osen emerged as the leading candidate to represent her, rather than jostling with all the others for her attention. “I didn’t want to be seen as a victim,” Singer said. “His involvement with restitution to Holocaust survivors, particularly those with Swiss bank accounts, caught my attention, and I knew I wanted him to take my case. Gary treated me with dignity, and it gave me a sense that I was doing something—fighting back, even if it was just a small piece of the puzzle.”
Singer is an extraordinary person in her own right, and her entirely volunteer-led organization is a mold-breaker in dealing with the trauma of either surviving terrorist attacks or being the surviving family members of those killed in them. And her work is not solely based on Israel and Israelis, although she has more recently worked with Nova Music Festival survivors from October 7, 2023.
“One victim impacts a minimum of eight people,” she said. “It doesn’t matter whether it was an attack at a Christmas market in Germany, the Boston Marathon, the suicide bomber at the Ariana Grande concert in Manchester, or the Alfred P. Murrah Federal Building in Oklahoma City bombing, the key to our success is peer-to-peer support.”
The structural problem of foreign aid
Osen’s work has also cast a spotlight on the failures of foreign aid mechanisms. He’s critical of agencies like USAID, which, in their eagerness to show results, often partner with groups that are either complicit in or turn a blind eye to terrorism.
“USAID doesn’t train up Americans who learn Arabic and know the environment like Peace Corps volunteers. They subcontract to organizations that subcontract again, with little understanding of who’s really on the ground,” he says.
Even the United Nations Relief and Works Agency (UNRWA), the U.N. agency for Palestinian refugees, has long been accused of harboring Hamas sympathies within its staff and leadership—charges that Osen and others believe have been ignored for decades by the international community.
Why it matters
What makes Osen’s mission essential is not just the chance of financial compensation for the victims—most never see a dime—but the principle of accountability. It’s about showing that no bank, government, or front company should get a free pass when their money fuels bloodshed.
“The war on terrorism isn’t only fought with bombs and drones,” Osen says. “There’s a financial front. And if you can choke off the funding, you’re forcing terrorists to make harder choices.”
For many of his clients, the journey is cathartic. “We didn’t move on,” Singer said. “But we learned how to carry on. Filing the lawsuit was a little sigh of relief—it was someone saying, ‘Yes, what happened to you was wrong, and someone should be held accountable.’”
After more than 20 years, Osen knows how steep the road remains. Governments will continue to prioritize diplomatic expediency. Financial institutions will continue to fight liability. And terrorist groups will find new ways to skirt the rules.
But none of that deters him.
“We’re not looking for thanks,” he says. “This isn’t about accolades. It’s about doing what needs to be done. If we can prove the case and shine a light on the facts, then we’ve done our job. That’s enough.”