Three men have been arrested after a pig's head was thrown into the car park of a mosque in West Sussex.
Police were alerted by people attending Langley Green mosque, in Crawley, on Saturday after a white car drove by.
A 21-year-old man from Horley was arrested nearby on suspicion of a racially or religiously-aggravated public order offence, police said.
On Sunday two other men, aged 20 and 25, both from Crawley, were also held. All three have been bailed until May.
Ch Insp Steve Curry, Crawley district policing commander, said: "While this was a very unusual incident, it has obviously caused great distress to those involved and we have worked closely with community leaders in dealing with the matter.
"This was immediately declared a racist incident and is being investigated as such.
"Crawley is a diverse and generally peaceful community and any incident aimed or likely to cause unrest will be robustly dealt with, as our rapid response to this incident has shown."
Farakh Jamal, secretary of the Crawley Islamic Culture Centre, said: "This unprovoked incident was intended to cause hate and incitement towards racial or religious hatred.
"We have urged the community not to react and are grateful for their resilience in dealing with this situation.
"We are also grateful to the authorities that as soon as the incident was reported, swift action was taken and within 24 hours three suspects were apprehended.
"At Langley Green Mosque we have always strived to work with other faiths and other communities and to come to a common ground, as the Holy Quran instructs.
"Interfaith dialogue is of utmost importance for healthy community cohesion our society needs. Keeping this at the forefront, we would not wish any faith or group to be recipients of such intolerance."