- The FBI's involvement is a routine step when US citizens are killed overseas
- Another US official said FBI investigators are on the ground in Niger providing technical assistance
Another US official said FBI investigators are on the ground in Niger providing technical assistance and helping to gather and evaluate evidence related to the attack.
The investigators are based out of US embassies in nearby African countries, the official said, and reiterates the FBI role in Niger is not unprecedented, as the bureau often lends its expertise into terror investigations abroad.
The Wall Street Journal earlier reported
the FBI's involvement.
Three senior US officials have told CNN that Defense Secretary James Mattis wants answers regarding the ambush on October 4. The investigation will be an effort "to get all the facts correct," an administration official familiar with the review has told CNN.
Speaking to reporters Thursday, Mattis did not provide additional details into why the body of Sgt. La David Johnson was recovered nearly 48 hours after his 12-member team was ambushed by 50 ISIS fighters in Niger.
White House spokeswoman Sarah Sanders was asked Wednesday whether President Donald Trump was satisfied with the information he has received about the mission and ambush.
"I believe they're still looking into the details of that," Sanders replied. "But I don't think that the President can ever be satisfied when there's loss of life from men and women in uniform."