Racist posters have been put up at a Pakistani community centre and other buildings in Manchester.
Police say the offensive material was also posted through doors of houses and taped to the centre in Longsight, south Manchester.
A local library and St Luke's Primary School in nearby Ardwick were also targeted.
The posters are believed to have been distributed on Thursday afternoon and police are treating the matter as a hate crime.
They have not said what was on the posters or the nature of the racism, but have released a CCTV image of a young man they want to speak to in connection with the incidents.
Superintendent Dave Pester from Greater Manchester Police (GMP) said: "I am determined to find out who is responsible for these despicable crimes.
"Hate crime has no place in our community, and I would ask that anyone with information contacts the police.
"I am keen to identify a young man who was seen near to St Luke's Primary School on the Coverdale Estate in Ardwick around 12.45pm on Thursday February 16.
"If you have had similar material posted through your door, please get in touch with police."
Anyone with information is asked to contact police on 101 quoting incident number 2293 16/02/17, or the independent charity, Crimestoppers, anonymously, on 0800 555 111.