Brantford police are investigating an unspecified incident on Sarah Street.
Officers in cruisers and on foot were all over the area north of Sarah and south Colborne Street East on Monday night after 10 p.m.
Closer to 11 p.m., police had blocked off parts of Rawdon Street in the area of Arthur Street near Major Ballachey elementary school.
So far Brantford police have not disclosed the nature of the incident under investigation, but say officers will be present in the neighbourhood throughout Tuesday.
Police are asking anyone who lives in the area with video surveillance footage from Monday to contact them at 519-756-0113.
Const. Shane Seibert says more information will be released Tuesday, as it becomes available.