The son of America’s longest-held hostage said an Iranian tied to his father’s kidnapping took part in the first round of peace talks.Dan Levinson, son of former FBI agent Robert Levinson, argued it’s a "slap in the face" to his family to have the official involved in talks as the United States and Iran teeter on the edge of a fragile ceasefire."There’s only a few people in the world who know exactly what happened to my dad, who were involved in what happened to my dad. The FBI identified five of them," Levinson said on "Fox & Friends" Tuesday."One of them was killed in the initial airstrikes at the start of this conflict. And another one is hiding in plain sight," he added.ONE AMERICAN'S DETENTION IN LEBANON EXPOSED A TRUTH THAT IS NOW DEVASTATING AN ENTIRE COUNTRYRobert Levinson is the longest-held hostage in U.S. history after vanishing in 2007 on Kish Island. He was working as a CIA contractor at the time of his disappearance. In 2020, U.S. officials announced they believed he had died in Iranian custody, though his remains were never recovered.EX-CIA OFFICIAL SAYS TRUMP'S 'HANDSHAKE' DEAL WITH CHINA COULD CUT OFF IRAN'S WEAPONS, END CONFLICTDan Levinson is now calling out Reza Amiri Moghadam, Iran's current ambassador to Pakistan, who took part in the first round of high-level talks in Islamabad. Levinson said Amiri Moghadam was one of several individuals identified as having a direct role in his father's abduction nearly two decades ago."It’s a slap in the face to our family, slap in the face to the United States of America," Levinson said, adding, "It hurts their [Pakistan’s] credibility as an independent intermediary between the two countries because they're allowing this man to take part in all of this."WIFE OF US HOSTAGE KEITH SIEGEL PLEADS FOR HOLIDAY MIRACLE: 'WE NEED TO GET THEM BACK'The two-week ceasefire between the U.S. and Iran is due to expire this week. Representatives from both nations are expected to return to Islamabad for a new round of talks. Vice President JD Vance is set to lead the U.S. delegation in Pakistan Tuesday.Levinson offered a warning for the negotiators, noting his family’s long history of dealing with the regime during his father’s captivity. He argued Iran only responds to "pressure" and "strength.""They don't understand kindness. We learned that in almost two decades of dealing with the Iranians," Levinson said, adding that the U.S. "need[s] to keep confronting them and calling them out on things like this."It’s a sentiment echoed by President Donald Trump during a recent interview with FOX Business’ Maria Bartiromo. When asked why his voice was hoarse, Trump told Bartiromo it was because he had been "screaming at Iranians all day," adding, "Because that’s the only thing they understand. They don’t understand being nice. They understand the way I have to do business."