TORONTO -- Police have released suspect photos as they investigate anti-immigrant posters being placed on libraries, schools and other sites in Durham Region over the span of several months.

Durham police said either a person or multiple people have plastered white and black posters with discriminatory messages toward immigrants across the region between October 2019 and February 2020.

Police released surveillance images connected to the case on Thursday.

Police are releasing surveillance images of possible suspect(s) involved in placing posters around Durham Region with discriminatory messages toward immigrants. https://t.co/qDxYmtMOC3 pic.twitter.com/w0SqNCFcj3 — Durham Regional Police (@DRPS) February 13, 2020

The first of the four images, captured in October 2019, shows a suspect holding a piece of paper at the Memorial Cenotaph in Port Perry. The second image is from November 2019 and shows a suspect holding a piece of paper at the Diane Hamre Rec Complex in Newcastle.

The more recent two images show a person with a paper at Brooklin High School in Whitby in February 2020 and at the Central Whitby Library in February 2020.

Police are asking anyone with information to contact the Central West Community Resource Unit at 1-888-579-1520 ext. 1850 or Crime Stoppers anonymously at 1-800-222-TIPS (8477).