The Los Angeles County Sheriff's Department is investigating one of their own officers after video surfaced showing him punching a special needs woman in the face.
Passenger Jermaine Green, who recorded the incident on his cell phone, said that 42-year-old Julie Nelson had been polite before two deputies tried to remove her from the bus.
"They said get off the bus," Green recalled to NBC's Los Angeles affiliate. "She then started cursing at (the female deputy). You could tell she had special needs. After that they grab her, she curses him out, calls him a big shot, next thing you know he gives her a big shot."
In a 911 call released Wednesday, a caller said Nelson had threatened to "beat up" other passengers. Sheriff's spokesman Steve Whitmore said she also had a four convictions of violence against police officers.
Nelson, who is homeless and known to be living behind a CVS Pharmacy, was taken into custody on a 72-hour psychiatric hold without being arrested.
At a press conference Wednesday, Sheriff Lee Baca admitted that the video was "disturbing."
"If the deputy who swung an elbow at the lady is looking at that as a sensible solution, we need to retrain that individual and hold him accountable," he explained.
Childhood friends of Nelson told NBC L.A. that she had a history of mental problems, but had not been taking her medication.
"We're going to take her and put her somewhere safe, same thing we always do, feed her, help her out, we love her," one friend said.
Watch the video below from NBC L.A., broadcast Jan. 11, 2012.
View more videos at: http://nbclosangeles.com.