PRINCE WILLIAM COUNTY, Va. (DC News Now) -- A student in Prince William County reported she was assaulted in a high school school bathroom, according to a letter forwarded to DC News Now on Friday. In the letter, Osbourn Park High School Principal Lisamarie Kane said they were only recently made aware of the allegations, despite the incident happening earlier in the school year. The Prince William County Police Department (PWCPD) said that the student was an adult female. She reported that she was in a bathroom near the gym on the first floor of the school when someone entered her stall and sexually assaulted her. The incident happened in August, during the first two weeks of the school year, PWCPD said. Bark Social files for bankruptcy, closes all locations across DMV "As soon as our administration team was made aware, our school resource officer and law enforcement officials began an investigation," Kane wrote. PWCPD officials said the school resource officer began investigating on Nov. 15. She added that the school is providing support to the victim and their family and cooperating with authorities as they investigate. The student told police the suspect was wearing an animal costume mask and was about 5'8" or 5'9" at the time of the attack. "Considering this incident, we will be implementing additional safety measures, including increased supervision in shared areas, limiting access to [the] bathroom during instructional time, and ongoing education and support for students on safety and reporting procedures," the letter continued. Counseling services are available to students and anyone with information is asked to contact police, she said. It was not made clear whether the person responsible was a student.