A group of teenagers ambushed and robbed a 14-year-old, rendering the boy unconscious during what a prosecutor described as a "savage beating".
Footage of the violent robbery has been played in the ACT Magistrates Court.
"Don't snitch," one woman, who was 18 at the time of the incident but is not named, was recorded saying to the victim following the "protracted assault".
Special magistrate Rebecca Christensen handed that woman an 18-month good behaviour order for her involvement in the crime.
The offender, who was also ordered to complete 50 hours of community service, did not directly partake in the violence but was instead sentenced on the basis of being "knowingly concerned".
All other allegedly offending parties involved were minors at the time of the incident and the status of their legal proceedings is unknown.
"Please stop," the young victim was recorded saying repeatedly through tears on the graphic footage.
The video showed the victim being kicked, and stomped on the head and body multiple times.
Agreed facts state the victim was riding a scooter while approaching an underpass in Kambah on the afternoon of June 15, when he saw three males and two females hiding near an entrance.
The victim is said to have been struck across the back of the head, causing him to fall from the scooter.
One of the three awaiting teenage boys was allegedly holding a knife, and another a metal pole.
"I'm going to kill you c---," one male alleged offender said.
"Should I shove this [pole] up his arse?" another male alleged offender said.
The three male teenagers are accused of beating the victim, who was curled up on the ground to protect himself and rendered unconscious due to multiple head blows.
After regaining consciousness, the victim was allegedly restrained in a chokehold, thrown, dragged, and slammed head first into the concrete ground, before his shoes were taken.
According to court documents, the victim pulled a small kitchen knife from his waistband while seated on the ground.
The female offender sentenced on Thursday approached the victim and said: "Give me the f---ing knife now."
The victim's head was again allegedly stomped on and his phone was taken.
"Good boy," one of the males was recorded saying after forcing the victim to apologise.
Prosecutor Sam Bargwanna said that while no victim impact statement was provided to the court, "the photographs and the footage speak for themselves".
The victim suffered a concussion, multiple hematomas, and lacerations to his face and head due to what the special magistrate described as multiple "blunt force traumas".
Mr Bargwanna said the female offender was less culpable than those "dishing out the beating" but said general deterrence was an important sentencing consideration.
"The community needs to know this type of behaviour, exacting violence on the streets with a weapon and in company in order to obtain property, will be punished by the court," the prosecutor said.
On Thursday, defence lawyer Andrew Fraser described his client as having had a "relatively minor role" in the incident.
Mr Fraser said the female offender was a "troubled person" and "vulnerable, somewhat gullible" at the time of her offending.
The female offender has previously spent two days in custody for the crime.
"Now you know what it's like," Ms Christensen said.
