People seeking a quiet swim reacted with revulsion on Sunday after finding Slugs Bay in Mellieha spoilt by what appears to be engine oil.
The bay is a quiet cove below l-Ahrax tal-Mellieħa.
"I could not believe my eyes when I found the small cave and surrounding rocks spattered with what seems to be used engine oil.
"It's an unspeakable act of vandalism on such a beautiful, unspoilt area. One really questions the motive and sanity behind such a shameful act," one reader told Times of Malta.
Another said he noticed the vandalism earlier in the week.
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