Detective Lynch said the incident at the school was witnessed by a number of other children of similar ages.
A joint Police, CYPS and Ministry of Education team will be working with those children and their families over coming days to conduct interviews and provide them with support.
"Police have a good understanding of what occurred at the school. The investigation focus over coming days is to complete interviews with the young children who were in the classroom when the incident occurred. Due to their ages they will require specialist interviewing capability and support," Lynch said.
Police will complete the scene examination at the school today and the scene will be released back to the school as soon as possible.
The incident was contained to the school and Police are not seeking public assistance with the investigation.