Winnipeg police have charged four teenage suspects with sexual assault with a weapon and forcible confinement in connection with alleged incidents at St. John's-Ravenscourt School.

CTV News has learned officers moved swiftly to lay charges over concerns some suspects might flee the country. Some of the suspects had their passports seized.

Two of the suspects are from Nigeria, one is from China and one is from Alberta, CTV News has learned.

The four arrested include an 18-year-old, a 17-year-old and two 16-year-old suspects. They also face charges for uttering threats.

The charges stem from incidents that date back to September 2009, said police.

"There are a number of victims, or possible victims, that will be interviewed in the near future, but at this point there has only been one person interviewed," said Const. Jacqueline Chaput, spokesperson for Winnipeg police.

All four suspects had initial court appearances. The lawyer for the 18-year-old suspect said he will attempt to get his client bail.

"(He) has no prior contact with the justice system whatsoever and obviously is extremely anxious to get his client bail," said Sheldon Pinx, the lawyer for the 18-year-old suspect.

Court documents state a wooden stick was used in some of the alleged assaults.

CTV News has learned officers are investigating allegations of threats of sodomy in the incidents.

The child abuse unit and sex crimes unit continue to investigate and police said more charges are pending.

Sources said police faced delays in getting information they needed to further the investigation.

It took the school four days to report the assaults to officers, but school officials said they acted upon legal advice.

"And our legal counsel said first you talk to the parents," said Stephen Johnson, the head of SJR, on Wednesday. Last week, a letter was sent home to parents from the school.

On Apr. 14, officials with SJR said a total of four students were suspended after accusations of abuse first surfaced last week. Two of those students were expelled.

Officials with Child and Family Services have ordered the two suspended students also not be allowed back into the school until the agency makes recommendations on how to proceed.

Stephen Johnson from SJR declined to comment on camera on Thursday, but said a consultant will be brought in to review the situation and make sure incidents like this don't happen again.

Johnson said he wants a process of recovery to start at the school.

The suspects have been granted bail with a number of conditions, including that they stay away from SJR.

- with a report from CTV's Kelly Dehn