Forensics teams were at The Level at the scene of an alleged stabbing.
Police were called to the park in Brighton just before 4.15pm on Friday.
A section of the park was cordoned off and forensics teams could be seen investigating a pile of clothes.
Police remained in the area all evening and said to expect a heightened police presence while they continue their enquiries.
Forensics at the scene on Friday (Image: Sussex News)
A man was stabbed and taken to hospital with “serious injuries”.
Police believe it to be an isolated incident and there is “no danger to the wider community”.
A spokesman added: “Anyone with information which could help officers with their enquiries is asked to report it to police online or call 101 quoting Operation Danegate.
The police cordon (Image: Sussex News)
“Alternatively information can reported anonymously to the independent charity Crimestoppers on 0800 555111.”
A 30-year-old man was arrested on suspicion of causing grievous bodily harm with intent and has been released on conditional bail until November 18.
Yesterday afternoon, a man was “struck with a bottle” in Montague Street in Worthing town centre.
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