The FBI is now part of the investigation looking into the Niger ambush that took the lives of four U.S. soldiers Oct. 4.
FBI investigators, based out of U.S. embassies in nearby African countries, are on the ground in Niger providing technical assistance and helping to gather and evaluate evidence related to the attack, according to a CNN report on Friday.
Why are FBI officials assisting?
Defense Secretary James Mattis wants answers regarding the ambush, CNN reported.
An administration official familiar with the review told CNN that the investigation will be an effort "to get all the facts correct."
It's not unprecedented for the FBI to get involved with military operation investigations, an FBI official told the Wall Street Journal. However, it's not typical.
What do we know about the attack?
Not a lot.
U.S. officials are still working on a timeline and looking into the details of the attack. Staff Sgt. Dustin Wright, Sgt. La David Johnson, Staff Sgt. Jeremiah Johnson, and Staff Sgt. Bryan Black died in an ambush. Two Americans were also wounded.
Mattis did not provide additional details into why the body of Sgt. La David Johnson was separated from the group and recovered nearly 48 hours after his 12-member team was ambushed by 50 ISIS fighters in Niger during a news conference Thursday.
Sarah Sanders, White House press secretary, was asked by reporters on 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 said, according to CNN. "But I don't think that the president can ever be satisfied when there's loss of life from men and women in uniform."
Trump has spoken to all four of the families of the members of the U.S. Army Special Forces killed in Niger.