Three teens charged with sexually assaulting classmate during high school graduation party, prosecutors say
Three 18-year-olds are facing felony charges after prosecutors say they sexually assaulted a classmate inside a minivan during a high school graduation party in an Illinois suburb.
Kevin Niemiec of Prospect Heights, Zachary Mascolo of Arlington Heights, and Jon Clary II of Bartlett, all 18, were charged this week, months after the incident that allegedly occurred between the night of June 14 and the early morning hours of June 15.
According to DuPage County prosecutors, during a graduation party for Saint Viator High School students in Roselle, the trio was in a minivan with a female classmate when each of them sexually assaulted her.
The victim then went to a friend’s home and contacted her sister, who alerted their parents, authorities said. She was taken to the hospital for medical attention and they contacted the Roselle Police Department.
“The allegations levied against these defendants are extremely serious,” DuPage County State’s Attorney Robert Berlin said in a news release. “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 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,” he continued. “I commend the victim in this case for her courage and strength in bringing this matter to our attention.”
Arrest warrants were issued for the three teens on December 17, according to the DuPage County State’s Attorney’s Office. Mascolo was taken into custody four days later during a traffic stop near his home, authorities said. Clary and Niemiec turned themselves in at the DuPage County Jail the following day.
Niemiec appeared in court Tuesday, when a judge ordered him held in custody while awaiting trial. He is charged with three counts of criminal sexual assault and was denied pretrial release.
Clary and Mascolo appeared earlier in the week and were released under court-ordered conditions that prohibit them from possessing or consuming alcohol and from having any contact with the victim or her family.
Mascolo faces two counts of criminal sexual assault, and Clary faces three counts; both were granted pretrial release with conditions.
Niemiec is set to return to court on January 12, 2026. Mascolo and Clary are scheduled to appear again on January 27, 2026.
In a statement to WGN, Saint Viator High School emphasized that the alleged assault did not occur at a school-sponsored event.
“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,” the school said in a statement. “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,” the statement continued. “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.”
