A group of teenagers were caught by the police for vandalising the school fence.

vandalising 是动词 vandalise 的现在分词形式。vandalise 来自名词 vandal（破坏公物者）加上动词后缀 -ise，意思是"故意破坏公共或私人财产"。在英国英语中常用 -ise 拼写，在美国英语中对应的拼写是 vandalize。