Colorado police defended a video of an officer slamming a 22-year-old woman to the ground as a "standard arrest technique".
"The arrest of Michaella Surat by Fort Collins Police officers has generated a great deal of interest on social media and conversation in our community", he says.
According to the Fort Collins Police Department, the Surat's boyfriend had been involved in a disturbance with another man at bar on Thursday night.
Police spokeswoman Kate Kimble says the woman struck the officer after police detained her boyfriend.
She was told that she was free to go but that her boyfriend was not. Surat bonded out of jail and is scheduled to appear in court Wednesday.
Police-worn body cameras also captured the event, he said, though that footage will only be released after an internal review and criminal proceedings.
"This event will be thoroughly investigated", Fort Collins Police Services Chief John Hutto posted in a lengthy statement on Facebook.
The student's family has pointed out that she weighs just 115 pounds and has released photos of bruises on her chin and legs. At that point, he said, the footage will be made available to the public.
The 9-second video shows the officer apparently trying to get Surat under control. She says that video hasn't been released because the case is still open.
"I have a duty to preserve and protect the processes that our society has put in place to ensure that the questions surrounding this incident are answered in a fair and impartial manner", Hutto told NBC News.