The memo was dated Jan. 28 and signed by by Acting Director Todd Lyons.
A 37-year-old man was shot and killed Saturday morning in Minneapolis -- the second shooting of a U.S. citizen this month by federal agents in the city.
The shooting of Alex Pretti, an ICU nurse, ratcheted up tensions, as protesters clashed in the streets with law enforcement in the aftermath of the shooting.
The incident followed the fatal shooting of Renee Good, a 37-year-old mother, on Jan. 7.
Minnesota Gov. Tim Walz responded on social media to the news that the FBI is now leading the investigation into the shooting of Alex Pretti, suggesting the move is not unbiased.
"Trump's right hand cannot be responsible for investigating his left hand. We need an independent, impartial investigation now," he said in his post.
-ABC News' Isabella Murray
President Donald Trump, in a post to his Truth Social account overnight, called Alex Pretti an "agitator" and “perhaps” an "insurrectionist" after video of Prett's interactions with federal agents on Jan. 13 surfaced on social media.
Pretti was killed in a shooting by federal agents on Jan. 24 in an incident that sparked an uproar nationwide.
This is the first time the president has commented publicly on Pretti's Jan. 13 interaction with federal agents -- 11 days before Pretti got into a confrontation with federal agents when he was shot and killed in Minneapolis.
In the post on social media, Trump criticized the video of Pretti kicking a vehicle used by federal agents in Minneapolis, describing Pretti's actions as a "display of abuse and anger."
"Agitator and, perhaps, insurrectionist,” said Trump in the post. “Alex Pretti’s stock has gone way down with the just released video of him screaming and spitting in the face of a very calm and under control ICE Officer, and then crazily kicking in a new and very expensive government vehicle, so hard and violent, in fact, that the taillight broke off in pieces.”
The president further commended the ICE officers' actions, saying he was "calm and cool."
In the Jan. 13 video the president is referring to, Pretti is wrestled to the ground and surrounded by multiple agents after he kicked the car, escaping from the agents shortly after.
Before the video of Pretti's interaction with federal agents in Minnesota on Jan. 13 surfaced, Trump had been more cautious in how he characterized the shooting than several other administration officials.
Videos verified by ABC News show that Pretti appeared to be using his phone to record the agents before he was shoved by a federal officer. Seconds later, a federal officer repeatedly pepper-sprayed Pretti and then appeared to pull him into the street.
While Pretti seems to have been pinned on the street by officers, one of the agents is seen in multiple verified videos emerging from the scrum with a handgun that appears to match the weapon federal officials say Pretti was carrying. Before the first shot is fired, another agent can be seen drawing his own handgun, while another repeatedly hits Pretti before two officers fire their guns at Pretti.
In total, 10 shots were fired in less than five seconds, according to a forensic audio analysis of the videos. Pretti was declared dead on the scene.
The Justice Department has opened an investigation into the killing of Alex Pretti by federal agents, Deputy Attorney General Todd Blanche said Friday.
"This is what I would describe as a standard investigation by FBI with our circumstances like what we saw last Saturday, and that that investigation to the extent it needs to involve lawyers of the Civil Rights Division, that will involve those," the Deputy Attorney General said at a press conference, adding there is coordination with the Civil Rights Division saying "they will be part of that effort."
The comments come as officials said that the Department of Homeland Security was leading the investigation. Blanche said both investigations are happening.
He said he wasn't committing to releasing body-worn camera from the incident. It would be "completely unfair to the investigation itself," Blanche said.
-ABC News' Pierre Thomas, Jack Date and Luke Barr
Former CNN journalist Don Lemon has been arrested in connection with a Jan. 18 incident in which anti-ICE protesters disrupted a service at a Minnesota church, according to his attorney.
Attorney Abbe Lowell said in a Facebook post Friday that his client was taken into custody by federal agents Thursday night while he was covering the Grammy Awards.
"Don has been a journalist for 30 years, and his constitutionally protected work in Minneapolis was no different than what he has always done," Lowell said.
Read more here.
-ABC News' Pierre Thomas, Katherine Faulders, and Luke Barr
