Police who responded to a Highland Avenue dispute were trying to arrest a belligerent man on June 25 when someone from the crowd flung the rock, Clifton Detective Lt. Robert Bracken said.
The 19-year-old man had stood on top of a car and refused to cooperate -- aggravating the situation by inciting people, Bracken said.
Officers were unable to diffuse the situation despite several tries and then attempted to arrest him, the lieutenant said.
A struggled ensued, as he and officers hit the ground -- at which point someone threw the rock, he said.
Anyone with information that could help lead to an arrest is asked to contact the Clifton Police Communications Center at (973) 470-5911 or the Clifton Police Juvenile Division at (973) 470-5882.
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