The latest act of vandalism was reported just before 11.30am on Wednesday (July 16), when officers were called to the square to find damage to part of an outdoor exhibition.
The exhibition showcases 20 portraits alongside personal stories from people who came to the UK from the Caribbean between the late 1940s and the 1970s.
CCTV footage shows the suspect entering the square at 9.53am.
He’s described as being between 30 and 40-years-old, medium build, and using a walking aid or crutch.
He was last seen heading north along Brixton Road, passing Morley’s department store.
Police have released an image of the man and are urging the public to help identify him.
Officers say they’re keeping an open mind about his motive, but believe it’s unrelated to an earlier incident on July 3, when a different man was arrested after a separate act of vandalism at the same site.
That suspect, 24, has been released on bail while enquiries continue.
Police do not believe the first incident was racially motivated.
Anyone who recognises the man or has information is asked to call police on 101 quoting CAD 5870/16JUL25, or contact Crimestoppers anonymously on 0800 555 111.
Detective Chief Superintendent Emma Bond, who leads policing in the local area, said: “Both offences have understandably caused distress among the local community. We are liaising directly with the exhibition organisers to keep them updated on both our investigations.
“There will be an increased police presence in the area over the coming days and the public is encouraged to approach these officers directly with any concerns.
“We would also ask for help in identifying the man caught on CCTV – if you have any information please come forward.”
