Four male high school wrestlers from Norman North High School have been charged with rape for an incident in January in which two other male students, aged 12 and 16, were allegedly assaulted on the bus coming back from a tournament, according to CBS News.

The Norman Police Department has concluded its investigation into the incident, which has been confirmed by Norman North High School officials to have taken place on Jan. 9 as the junior varsity wrestling team was returning from a tournament, according to the Associated Press. The younger students were on board the bus because the team also includes middle school students, according to Tulsa World.

The four students, aged 17, 17, 16 and 18, have been charged with rape by instrumentation for the attacks, which consisted of restraining the victims and digitally raping them, according to News9. Both victims were assaulted at the back of the bus, and the 12-year-old involved was attacked further on school property before being collected by his parents, according to News9.

A statement released by Norman Public Schools superintendent Joseph Siano said that "student safety is a top priority and we followed procedures we have in place that allow us to effectively investigate and take swift action in these situations," according to News9. All four of the boys involved have been suspended, and one adjunct coach was fired as a result of the incident, with a second coach resigning later, according to News9. 

The oldest of the alleged perpetrators,18-year-old Tanner Shane Shipman, will be charged as an adult for the alleged assaults, which are classed as felonies, according to Tulsa World. The other boys involved are charged as youthful offenders. All of those involved were expected to turn themselves in on Tuesday, according to Tulsa World.