TORONTO -- Warning: This article contains graphic content that could be disturbing to some readers.

A former student of a Catholic all-boys school described before a Toronto court on Wednesday a sexual assault he said he witnessed on campus that involved members of the football team.

The teen said he saw three teammates pin down another student in a locker room at St. Michael's College School, while a fourth teammate wielded a broom handle.

He testified that he couldn't see who held the broom handle, but identified the three students involved in the incident that took place in November 2018, including one who is on trial on sexual assault charges.

The accused is charged with two counts each of gang sexual assault, sexual assault with a weapon and assault with a weapon related to two incidents in which students were sexually assaulted with a broom handle.

The incidents took place on school grounds in October and November 2018.

None of the teens can be named due to provisions in the Youth Criminal Justice Act.

The teen who testified Wednesday said the incident he witnessed occurred in the school's locker room - also known as "the dungeon" because it is in a basement, has no windows and only one door - after the school won a football game on Nov. 7, 2018.

While he was changing out of his gear, the teen said he heard yelling and walked toward a group of students huddled together. That's when he saw a student on the ground.

"They were pinning him down, he was swearing and telling them to stop," the teen testified.

The group didn't stop and someone shoved the broom handle into the boy's anus, he said.

The incident didn't last long and the victim, who wasn't on the team, got up quickly and laughed it off before leaving the locker room.

Earlier Wednesday, another former student told court he felt violated after the accused and several other members of the football team tried to rip his pants down one day that fall.

He told court on Monday that the accused had made hazing at the school more violent and more sexual.

"I felt kind a violated by it and it took a whole year before I told anybody," he said.

He said the broom loomed large in the locker room and players were often hit on their butts by the team's leaders.

He said he did not witness the sexual assaults, but saw the accused and three others circling one teen just before one of the incidents occurred.

During cross-examination by the accused's defence lawyer, the testifying teen denied making fun of the victim for being sexually assaulted.

A student captured the November sexual assault on video, which was then shared widely in the school on Snapchat, court heard.

The video, which was played in court in March 2020 when the trial began, shows a boy being sexually assaulted as others cheered and laughed.

There is no known video of the October sexual assault.

In December, court heard one complainant describe to police being sexually assaulted with a broom handle by a group of students in the school's locker room in October 2018.

In the second recording, he recalled seeing a group sexually assault another student in a similar way the following month, also in the locker room.

The complainant did not mention the accused when discussing the October incident, but alleged the teen held back the arms of the victim in the November assault.

The complainant was initially one of the suspects in the November 2018 incident, but the charges against him were dropped.

Three teens have pleaded guilty to sexual assault with a weapon and assault with a weapon for their roles in the incidents and have been sentenced to two years of probation.

One of them also pleaded guilty to making child pornography for recording one of the sex assaults in a video that was then widely distributed.

Another student received a two-year probationary sentence with no jail time after pleading guilty. The charges against another student, aside from the one who testified, were withdrawn.

This report by The Canadian Press was first published Feb. 3, 2021.