(CNN) -- A Massachusetts teen accused of raping a fellow student at a summer sports camp pleaded not guilty Tuesday.
Galileo Mondol, 17, is one of three high school junior varsity soccer players who authorities allege entered a cabin occupied by freshman students and assaulted three victims at a camp in western Massachusetts.
At Tuesday's hearing, prosecutors said the three went into the freshman cabin searching for victims, using a broomstick to assault them.
Attorney William Korman told CNN that Mondol was an innocent bystander and actually tried to stop the other students from getting involved.
Mondol is being tried as an adult and faces charges that include aggravated rape of a child under 16, indecent assault and battery on a person who has turned 14, assault and battery and intimidation of a witness.
On Tuesday, he should have been heading to school for the first day of classes.
"I imagine he planned on getting dressed for his first day of school, and instead he had to get arraigned on felony charges," Korman said. "He's very mature for his age. He understands the severity of the charges, but he's also confident because he knows he didn't do anything. He knows he will be exonerated."
Mondol is being held without bail pending a "dangerousness" hearing Friday, Korman said. If Mondol is found to be dangerous, the judge can continue to hold him without bail for 90 days. If the judge finds him not dangerous, his bail will be set at $100,000.
Two other JV soccer players, both 16, face similar allegations, prosecutors said in a statement.
It was unclear Tuesday whether they had been arraigned or entered pleas in response to the charges. Frederick Lantz, a spokesman with the Berkshire District Attorney's office, said he could not reveal details about their cases because they were minors.
The assaults occurred last month at Camp Lenox near Otis, a town in western Massachusetts, according to the Berkshire District Attorney's Office.
The city of Somerville, just northwest of Boston, rented the facility for team-building activities for its fall sports teams.
A criminal investigation began after the allegations were reported to members of the Somerville High School athletic department.
"We are disturbed and appalled that these crimes may have taken place," Somerville's mayor and schools superintendent said in a joint statement, "and our thoughts and concerns are with the victims and their families."
CNN's Christine Theodorou contributed to this report.