Federal agents said the findings of the routine investigation will be forwarded to the Civil Rights Section of the Department of Justice in Washington, D.C.
Meantime, police sources have identified Officer Mary Woollum as the second officer involved in the April 17 beating captured on tape.
The video, which shows two Seattle police officers kicking and shouting a racial threat at an innocent man as he lies on the ground, has set off a firestorm of controversy around the world.
Officials said FBI agents will collect evidence and forward the findings to the Civil Rights Section of the Department of Justice in Washington, D.C.
The footage shows what started as a police hunt for a robbery suspect. Officers caught a man they later learned was the wrong guy.
The video shows Det. Shandy Cobane, a member of the gang unit, on the scene as Seattle police detained three people, including one Hispanic man, in their hunt for possible armed robbery suspects.
A man can be seen lying face down without handcuffs and not under arrest.
On the video, you can hear an officer telling the man: "You got me? I'm going to beat the (expletive) Mexican piss out of you homey. You feel me?"
Seconds later, the man moves his hand, appearing to wipe his eye. The officer kicks him in the head as he wipes his boot on his hand. A female officer, now identified as Woollum, stomps on his leg.
Police realize they detained the wrong man, lift him up, and let him go. The video does not show a medic arriving on scene, even though the man has cuts on his face, and appears to have trouble walking.
Since the footage was made public, Cobane has stated he regrets his actions that night.
"I chose words as part of my conversations with that young man that were offensive and unprofessional," Cobane said.
Cobane has been reassigned while the Seattle Police Department conducts an internal affairs investigation. It is not known whether Woollum has also been reassigned.
Those who knew the beaten man said he never expected to end up in such a situation, and has hired an attorney.
"(He is) very calm, very respectful, very elegant, eloquent," said Roberto Maestas of El Centro de la Raza. "Just a good kid, good kid."
Maestas, a member of the SPD Chief Search Committee, and says the images on the tape will influence his decision.
"They can not, will not, must not withhold their help just because the person on the other side is not of one or another color," he said.
The selection panel interviewed the 9 candidates over the weekend, and will present its top three to the mayor on Tuesday.