If the assault had occurred where it was seen and brought to the school's administration at the time of the incident, many schools today have a police officer on campus and the assaulting student would likely have been charged with assault - either ticketed and suspended or arrested with the parents having to go to the local jail to arrange for their child's release. I've seen both happen.
There may also be more to the incident of which we are unaware - extenuating and mitigating circumstances found in the investigation but not open for discussion as they are part of the privacy policies common with official school records.
When something like this comes to light days or weeks later, and depending upon the state and local school discipline policies in effect,
'after the fact' suspension is also acceptable and such a suspension (normally with no work being accepted during the time of the suspension) can have a serious effect on a student's scholastic record - including failed required course(s) if it occurs during a critical exam/term paper time, removal from all exra-curricular activities and sports, and a denial of college acceptance (colleges specifically ask for such info from schools upon application and do consider an applicant's character for admission). The liklihood of removal to an 'alternative school' and even expulsion may still exist here if further information comes to light at some point.
Additionally, at my school, we would have
advised all familes involved of the potential for further disciplinary and legal action(s) against the student who committed the assault, sent an information letter concerning the incident and its disposition to all our school families with a recommendation they sit down and review the school's Code of Conduct policies with their children, and had faculty advisors review the school's Code of Conduct and the potential repercussions of misconduct with their students during their daily advisory period .
It will be interesting to see if there is any further news reported about this incident.
Richard