-- A video posted to Facebook captures an Arizona police officer punching a woman in the face while attempting to arrest her.
The video shows a woman repeatedly saying she did not do anything wrong and asking if there is a warrant for her arrest.
"You cannot arrest me until I know that I have a warrant," the woman says, while two Flagstaff police officers continue with the arrest.
Suddenly, one of the officers punches the woman in the face, while her acquaintance shoots the video. Someone is heard on the tape calling her "Marissa," saying, "Hey, you can't hit a girl like that."
After a few seconds, the woman starts crying and the officer continues with the arrest.
"You're going to get tased," he is heard saying. "Get on the ground."
The video of the incident has been shared on Facebook 78,000 times so far.
The Flagstaff Police Department said in a statement that on Wednesday evening it "became aware of a Facebook video post of a Flagstaff Police Officer involved in the arrest of an adult female earlier this afternoon."
The department identified Officer Jeff Bonar as the arresting officer and said he has been placed on administrative leave while the incident is under investigation.
The Flagstaff Chief of Police Kevin Treadway said at a news conference Thursday that the video "clearly depicts" Officer Bonar striking the woman "in the face with his fist."
"I am as concerned about what is depicted in the video as I know many others are," Treadway added.
Treadway said they have launched an internal affairs investigation and have also asked the Northern Arizona University Police Department to conduct an independent investigation into the incident.
"So often in cases like these there is a rush to judgment and a call to immediate action," Treadway said, but added that they owe the whole community a "full and complete" investigation.
Bonar had been with the department for just under three years, he said.
According to Sgt. Cory Runge of the Flagstaff Police Department, Bonar had recognized the woman, "as previously having a warrant, which he believed was still valid." He approached her for this reason, he said, and "attempted to detain her while he verified whether the warrant was valid or not."
Treadway said that Bonar filed a report on the incident as well. "In that police report the officer does indicate that he was kicked and that he was knee-ed in the groin prior to the strike occurring," Treadway said.
ABC News attempted to reach Bonar for comment.
The woman who was punched during the attempted arrest has been identified as Marissa Morris. She was released after police confirmed her previous warrants had been cleared. The Flagstaff Police Department has not yet responded to ABC News' request for further comment.