Eli Lisack AKA Goliath, was an Israeli-born arms dealer.
Despite his nationality, Lisack felt no particular loyalty to his country; although, as he was quick to point out, he did not sell weapons directly to Israel's enemies, like Hamas and Hezbollah, Ziva David was quick to angrily point out that he sold to other people who sold such weapons to them in both Hebrew and English.
As a favor to Mossad, a NCIS team kidnapped Lisack in Washington, D.C., and prepared to extradite him to Zaire, the government of which still bore a grudge against him for an arms deal that had gone sour. In exchange for Lisack, the Zaireans would trade a valuable piece of intelligence to Mossad, who would trade an equally valuable piece to the U.S.
Knowing that he was heading for what would likely be a messy and painful death, Lisack tried desperately to trade information in exchange for amnesty. He revealed that ARES (a computer program controlling the guidance systems of U.S. cruise missiles) was being offered on the black market, a tip that eventually led the NCIS team to the French arms dealer René Benoit.
Lisack believed he had negotiated an agreement to release him in Portugal, safely outside U.S. jurisdiction. He was severely disappointed when the plane touched down in D.C. again, indicating that, though he had escaped a messier fate in Zaire, he would still be prosecuted under U.S. law.