FORT LAUDERDALE, Fla. -- An alleged sexual assault on a mentally and physically handicapped student at a Broward County middle school went unreported for days, authorities said.

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The victim and the accused are all special needs students at the school.

The alleged assault took place in the parking lot of William Dandy Middle School in Fort Lauderdale on Wednesday Dec. 19.

A teacher said she saw two 13-year-old boys sexually assaulting an 11-year-old girl.

The teacher who witnessed the assault alerted security immediately, but nothing was done, police said.

It wasn't until two days later that the incident was reported to authorities after a school resource officer overheard a witness discussing the assault.

School district officials said they want to know why it took so long for the assault to be reported to authorities.

"There was at least a day, if not longer, before it was actually reported to the principal so the principal can go through the proper notifications," said Keith Bromery, Broward County School District representative. "It was also not reported to the child abuse hotline, which was required to happen based on the nature of the incident that occurred."

The case is under investigation. There was no word on what kind of disciplinary action or criminal charges the accused students will face.

The principal reinforced with the school staff the proper steps that should take place when an incident like this occurs.

Stay with NBC 6 and NBC6.net for more details on this report as they are released.