When Dana is interrogated by Goren and Eames, she tells the detectives that the stash is at a warehouse, and both she and "Chilly" have a key. The scene shifts to police using bolt-cutters to remove the lock, only it's a combination lock, not a keyed lock. Dana goes on to insist that only the two of them had keys; however, some combination locks are hybrid and have key bypasses. In this case, though, the locks she and Chilly place on the door are rubberized padlocks with no combination dial.
A critical point of the story is that an ancestor of one of the characters, a Josiah Roundtree, was a Quaker turncoat who, because of greed, became involved in importing slaves into the United States, around the time of the Civil War. Problem is, no slaves were imported into the U.S. after 1808; the Constitution ruled it out: see Article I, Section 9.
Lifting a 5 gallon bucket of gold coins: Approx. mass of water (pounds per gallon @ 62°F) = 8.33. 5 Gallons of water would be 41.65 pounds. Gold is 19.3 times the density of water.
5 Gallons of gold would be 803.85 pounds.
It is true that The Act Prohibiting Importation of Slaves of 1807 made it illegal to import slaves into the United States starting in 1808. However, before Proclamation 95 (also known as the Emancipation Proclamation) this law was not really enforced, especially in the southern states. Before and during the Civil War slaves were smuggled into the United States under the radar, and when the Confederate States of America was formed they, of course, abolished that act in all but writing and openly imported slaves from Africa into the South in an attempt to replace some of the slaves that ran away to the North. So it is entirely possible, probable even, that Simon Harper's ancestors were involved in the slave importation business around the time of the Civil War.
When the Major Case detectives meet with Agent Corbett (FBI) and Inspector Lindsay (Scotland Yard), they are shown an image of Tarek Agiza's U.K. passport. The passport says Agiza's place of birth is Great Yarmouth which is a resort town in England, but moments later, Inspector Lindsay says Agiza was "born in Egypt".