York Regional Police are investigating an incident of graffiti at Markham District High School weeks after attending the school for two similar incidents.

It was on Aug. 20 that racial slur graffiti was first discovered at the school.

Police were then on the grounds of the Church Street school again Aug. 24, when someone sprayed the word 'Nazi' on a portion of pavement.

The new graffiti contains messages including "death to cops and nazi".