A teenager was attacked because he had an earlier dispute with another student who is a family member or associate of the four adults, Sayreville police said.
Video evidence recorded by bystanders at about 2:15 p.m. on Washington Road shows an adult pulling a knife and beating the victim, police said.
Two men were arrested in nearby Kennedy Park.
Two other men — one of whom was in possession of a knife — were arrested about two hours later after police posted a photo of one of them on Facebook..
The student who was attacked suffered minor injuries. He was not stabbed, police said.
Christoper E. Torres, 24, of Staten Island, is charged with aggravated assault and conspiracy to commit assault.
A 25-year-old Brooklyn man and a 19-year-old Staten Island man were both charged with assault and conspiracy to commit assault. A 27-year-old Staten Island man was charged with possession of metal knuckles.
A brief shelter-in-place at Sayreville High School was lifted after the incident.
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