WASHINGTON (AP) -- U.S. special forces seized a "key leader" of the deadly Benghazi, Libya, attack and he is on his way to face trial in the U.S. for the fiery assault that killed the U.S. ambassador and three other Americans, the Obama administration announced Tuesday. It was the first breakthrough in the sudden overseas violence in 2012 that has become a festering political sore at home. President Barack Obama said the capture on Sunday of Ahmed Abu Khattala sends a clear message to the world that "when Americans are attacked, no matter how long it takes, we will find those responsible and we will bring them to justice." "We will find you," Obama declared. As recently as last August, though, Abu Khattala told The Associated Press that he was not in hiding nor had he been questioned by Libyan authorities about the attack at the diplomatic compound. He denied involvement and said that he had abandoned the militia. Administration officials said Tuesday that despite his media interviews, he "evaded capture" until the weekend when military special forces, including members of the Army's elite Delta Force, nabbed him. Whatever the path to his capture, he was headed for the United States to face what Obama called "the full weight of the American justice system." Obama called the Libyan an "alleged key leader" of the attack. U.S. officials said Abu Khattala was being held on the Navy amphibious transport dock ship USS New York, which was in the Mediterranean Sea. The officials spoke only on condition of anonymity because they weren't authorized to discuss Abu Khattala's whereabouts. The Libyan was the commander of a militant group called the Abu Obaida bin Jarrah Brigade and is accused of being a senior leader of the Benghazi branch of Ansar al-Shariah in Libya, which the U.S. has designated a terror group. On Capitol Hill, Republicans urged the administration to get as much intelligence out of Abu Khattala as possible before anyone reads him his rights to remain silent, supplies him with a lawyer and prepares him for trial in a U.S. courtroom. In fact, Sen. Saxby Chambliss of Georgia, top Republican on the Intelligence Committee, said interrogation of the Libyan already was underway and "we hope to find out some positive things." Abu Khattala is charged with terror-related crimes in U.S. District Court in Washington and will be tried like a civilian, the administration said. The Obama administration policy is to treat terror suspects as criminals when possible and not send them to the military prison in Guantanamo Bay, Cuba, like hundreds of terror suspects captured during the administration of President George W. Bush. Republican Senate leader Mitch McConnell of Kentucky said the U.S. should skip the legal niceties and focus on interrogation. "The most valuable thing we can get from this terrorist is information about who else was involved in this," McConnell told reporters. "We'll be watching closely to see how much information they glean from him and how they're handling it." Sen. Lindsey Graham, R-S.C., added: "We should have some quality time with this guy -- weeks and months. Don't torture him; have some quality time with him." Justice Department spokesman Marc Raimondi declined to comment on whether Abu Khatalla had been read his "Miranda rights" or when that might happen. "As a general rule, the government will always seek to elicit all actionable intelligence and information we can from terrorist suspects in our custody," Raimondi said in an email. The Sept. 11, 2012, attack in Benghazi, on the 11th anniversary of the World Trade Center attacks, killed U.S. Ambassador Chris Stevens and three other Americans. Stevens was the first U.S. ambassador to be killed in the line of duty in more than 30 years. In the immediate aftermath, political reaction formed along sharply drawn lines that hold fast to this day. With the presidential election near, Republicans accused the White House of intentionally misleading voters about what sparked the attack by portraying it as one of the many protests over an anti-Muslim video made in America, instead of a calculated terrorist attack on the president's watch. Obama, for his part, accused the Republicans of politicizing a national tragedy. After 13 public hearings, the release of 25,000 pages of documents and 50 separate briefings, more congressional hearings are yet to come. One element in the ongoing political situation: The attacks unfolded while Hillary Rodham Clinton, now considered a likely Democratic presidential candidate, was secretary of state, and Republicans have faulted her words and actions in many respects. According to a criminal complaint unsealed Tuesday, Abu Khattala is charged with killing a person in the course of an attack on a federal facility and conspiring to do so; providing, attempting and conspiring to provide material support to terrorists that resulted in death, and discharging, brandishing, using, carrying and possessing a firearm during a crime of violence. Officials said he could face the death penalty if convicted of the first charge. His arrest may well not be the last. "Even as we begin the process of putting Khattala on trial and seeking his conviction before a jury, our investigation will remain ongoing as we work to identify and arrest any co-conspirators," Attorney General Eric Holder said. FBI Director James Comey, speaking in Minnesota, said Abu Khattala's arrest sends a message to others who need to be held accountable that "we will shrink the world to bring you to justice." Some Republicans said Abu Khattala should be headed for Guantanamo so that he could be interrogated at length. "The president is more focused on his legacy of closing Guantanamo Bay than preventing future terrorist attacks like what happened in Benghazi," said Sen. Jim Inhofe, R-Okla. Senate Judiciary Committee Chairman Patrick Leahy, D-Vt., countered that Abu Khatalla can be brought to justice in U.S. courts "just as we have successfully tried more than 500 terrorism suspects since 9/11." He said sending the Libyan to Guantanamo would be taking "the easy way out." National Security Council spokeswoman Caitlin Hayden said in an email statement: "We have not added a single person to the GTMO population since President Obama took office, and we have had substantial success delivering swift justice to terrorists through our federal court system." A witness interviewed by AP following the attack said Abu Khattala was present at the building when it came under attack nearly two years ago, directing fighters. Abu Khattala admitted being there but said he was helping rescue trapped people. As for the circumstances of his capture, Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, credited U.S. forces with "carrying out a dangerous and complex capture operation resulting in no casualties." The Pentagon press secretary, Navy Rear Adm. John Kirby, said that regardless of how openly the Libyan was said to have been living, the important point was that he now is in custody. "Let's just say for argument's sake he was living in plain sight; he's not anymore," Kirby said. People should not think this was a situation where "he was going to McDonald's for milkshakes every Friday night and we could have just picked him up in a taxi cab," he said. "These people deliberately try to evade capture." As the U.S. raid took place on Sunday, forces loyal to a renegade general attacked Islamic militant camps in Benghazi as part of a new assault against the groups. Airstrikes targeted the camps on behalf of Gen. Khalifa Hifter, who was a top military official under dictator Moammar Gadhafi but later defected and lived for years in the U.S. It isn't clear what the strikes targeted. The general later said the clashes killed five of his fighters. Hifter's forces have targeted Ansar al-Shariah.