Holder arrived Sunday in London, the first of three European cities he will visit seeking allies' help to close Guantanamo Bay, fight terrorism, and catch cyber-criminals.
The attorney general and his staff took a tour of the Tower of London, home of The Bloody Tower, and also the site where Guy Fawkes was put on the rack in 1605 to name those plotting with him to blow up Parliament.
The tower visit is standard fare for tourists, but one loaded with extra meaning for Holder, who listened quietly to tales of torture, execution, and palace intrigue.
The attorney general must decide whether Bush administration officials should be prosecuted for authorizing and approving harsh interrogation techniques against terror suspects. Critics call the methods torture.
Holder also has less than a year to empty the U.S. military detention facility in Guantanamo Bay, Cuba.
During the flight to London, Holder said in an interview with The Associated Press that the Obama administration is close to deciding what to do with an initial group of prisoners.
The attorney general did not say how much longer he thought it would take to relocate the Guantanamo detainees. Before officials can meet President Obama's January deadline, the U.S. must first decide which detainees to put on trial and which to release to the U.S. or other countries.
Holder said the first step is to decide how many total detainees will be freed.
"We're doing these all on a rolling basis," he said. "I think we're probably relatively close to making some calls."
The Obama administration is edging toward taking some prisoners to the U.S., most likely to Virginia. They are Chinese Muslims known as Uighurs, and their supporters say they never should have been at Guantanamo.
Currently, there are 17 Uighurs held at Guantanamo. In recent weeks, officials reinterviewed them in preparation for their eventual transfer.
The Uighurs were captured in Pakistan and Afghanistan in 2001. Uighurs are from Xinjiang, an isolated region that borders Afghanistan, Pakistan and six Central Asian nations. They say they have been repressed by the Chinese government. China has said that insurgents are leading an Islamic separatist movement.
Any country that takes them is likely to anger Beijing.
Republicans in Congress say Guantanamo should remain in operation and are mobilizing to fight the release of any detainees into the United States.
Some European leaders argue that if the detainees are to be released anywhere, it should be in the United States.
There are about 240 inmates at Guantanamo. As many as 60, if freed, cannot go back to their homelands because they could face abuse, imprisonment or death. They are from Azerbaijan, Algeria, Afghanistan, Chad, China, Saudi Arabia and Yemen.
Several European nations, including Portugal and Lithuania, have said they will consider taking such detainees. Some nations, such as Germany, are divided on the issue.