Taylor has been on trial for almost three years at the U.N.'s Special Court for Sierra Leone, which is being held at the World Court in the Netherlands, and has pleaded not guilty to all charges against him.
The warfare in Sierra Leone, where diamonds were used by African rebels and allegedly by Taylor to raise money for a bloody rampage from 1997 to 2001, killed or maimed tens of thousands. Taylor's lawyers have argued there is scant direct evidence that connects Taylor to the diamonds or the atrocities.
"The issue here is not whether such atrocities were indeed committed but who was responsible and specifically was Charles Taylor the person responsible," Courtenay Griffiths, Taylor's lead counsel, told ABC News.
Taylor has angrily denied dealing in blood diamonds. When pressed on the stand in November by Brenda Hollis about whether he sent his men to give a diamond to Campbell, Taylor called the allegation "total nonsense."