A Melbourne boy with autism was allegedly beaten with spanners and repeatedly punched and kicked by a group of teens.
A 15-year-old boy has been arrested in relation to the footage, a Victoria Police spokeswoman said on Thursday, as investigations continue.
The boy's mother said her son Quinn, 14, was allegedly set upon by five youths after they challenged him to meet them outside a school.
It's alleged he was pushed from his bike and attacked with spanners.
"No adult stopped to help, no one beeped their horn or did anything from their cars, which of course is another thing which is very distressing," She told 3AW radio.
"It's my husband's and my worst nightmare, and I know it's the worst nightmare of most parents who have an autistic child," she said.
Premier Daniel Andrews described it as a "terrible incident".
"As I understand it the school has taken this matter very seriously, as they should," he said.
"As bad as this incident was, as difficult as it is to comprehend, it's one of a very small number of incidents that we see across our schools."
"I watched that myself and (it's) really just disgusting behaviour against this young fella," he told ABC Radio.