A 16-year-old has been arrested after pieces of ham were thrown at a mosque.
The apparent hate crime was directed at the Broadfield Mosque, Crawley, around 4pm on November 20.
Officers were alerted after worshippers leaving the centre saw a youth throwing the meat.
A 16-year-old local boy has been arrested on suspicion of a religiously aggravated public order offence and has been bailed while enquiries continue.
Sergeant Jim Collen, from Crawley police, said: "This was a very unpleasant incident which has naturally caused real anguish and anxiety amongst worshippers at the mosque.
“Sussex Police take all reports of hate crime extremely seriously and this investigation will be no exception.
“We will deal with this matter robustly and I would appeal to anyone who witnessed this incident to contact the police."
Following the incident, there was further disorder which is also under investigation.
Sgt Collen added: "We are aware of a relatively minor altercation that we hope to resolve using our restorative justice programme.
“It must not be allowed to take the focus away from our investigation of the hate crime as this remains our priority."
Anyone with information should call police on 101 quoting serial 1005 of 20/11 or Crimestoppers on 0800 555 111.
See the latest news headlines from The Argus:
- Naked bike ride picture REMOVED from station's gallery after complaint
- Tarot reader tells how she revealed murder in her cards and killer confessed
- 10,000 people sign petition demanding railway franchise review
- Eastbourne shuns Blue Flag beach scheme due to 'enormous cost'
- The Argus EU debate to host EU debate