In Roselle, Illinois, three teenagers are facing serious accusations after allegedly sexually assaulting a female classmate during a graduation celebration at a suburban high school. This information was released by the DuPage County State’s Attorney’s Office on Tuesday.

Kevin Niemiec, an 18-year-old from Prospect Heights, has been formally charged with criminal sexual assault. He currently remains in custody as he awaits trial, according to the state’s attorney’s office.

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Also charged with criminal sexual assault is Zachary Mascolo, another 18-year-old, from Arlington Heights. Unlike Niemiec, Mascolo has not been detained and is not in custody at this time.

The third individual, Jon Clary II, also 18, hails from Bartlett. He appeared in court on Tuesday but, similar to Mascolo, is not being held in custody.

Under their pre-trial release conditions, both Mascolo and Clary are prohibited from consuming or possessing alcohol and must avoid any contact with the victim and her family, as directed by officials.

The incident came to light when Roselle police received a report on June 15 about an alleged sexual assault that took place the previous night at a Saint Viator High School graduation party in Roselle.

Officials said the defendants and the victim were in a minivan, where each of the teens sexually assaulted the victim.

The victim was taken to a local hospital after the incident.

Judge Michael Burton issued an arrest warrant for all three defendants on Dec. 17.

Mascolo was taken into custody Sunday, while driving near his home.

Clary and Niemiec turned themselves in to the DuPage County Jail on Monday.

“The allegations levied against these defendants are extremely serious,” DuPage County State’s Attorney Robert Berlin said. “A graduation party is a celebration of accomplishments and the excitement of a bright future. It is alleged that Mr. Clary, Mr. Mascolo and Mr. Niemiec violated the victim in the worst possible way and inflicted a lasting harm on a young woman. It is my sincerest hope that the victim and her family receive the care they require and deserve to help them cope with this horrific event. I commend the victim in this case for her courage and strength in bringing this matter to our attention.”

Niemiec is next due in court Jan. 12. Mascolo and Clary are due in court Jan. 27.

Saint Viator High School said in a statement:

“We were deeply saddened to learn today that criminal charges were filed against three St. Viator alumni involving another graduate of our School. These allegations-which come during the Christmas season-involve serious and troubling conduct which was reported over the summer in connection with an offsite private graduation party from this past June.

“This gathering which gave rise to the alleged criminal conduct took place in Roselle at a private, non-school-sanctioned event that was not sponsored, organized, supervised, or authorized by Saint Viator High School. Despite any reports to the contrary, this event was not at a “Saint Viator High School graduation party.” In fact, the event took place after the students who were allegedly involved in this crime graduated from high school.

“The safety, well-being, and dignity of our students are of utmost importance to our entire community. Saint Viator High School remains committed to fostering a culture of respect, responsibility, and care consistent with our Viatorian mission and values.

“We extend our sincere concern, support, and prayers to all those affected by this incident. Saint Viator High School will continue to cooperate with law enforcement. Because this matter involves ongoing legal proceedings, the School is unable to comment further at this time.”