U.C.L.A. Police Make First Arrest in Attack on Protest Encampment

More than three weeks after counterprotesters attacked a pro-Palestinian encampment at the University of California, Los Angeles, the university police have made the first arrest related to the attack: an 18-year-old who officers said had beaten pro-Palestinian protesters with a wooden pole.

The U.C.L.A. police did not identify the man by name, but arrest records show that he is Edan On. He is facing one charge of felony assault with a deadly weapon. The police said he inflicted serious injuries on at least one person.

In videos of the April 30 attack on the encampment, a man in a light-colored hoodie and a white mask is seen swinging a pole at several protesters. In one photograph, there appears to be blood on the sleeve of his sweatshirt.

Mr. On’s mother told CNN that the man seen in those videos was her son, though she later told the network that he had denied being there. She told CNN last week that her son was a high school senior with plans to join the Israeli military.

Mr. On was arrested on Thursday morning at a business in Beverly Hills, the police said. Jail records show that bail was set at $30,000.

Mr. On’s mother and father declined to comment on Friday.

The U.C.L.A. Police Department has been under intense pressure to identify and charge counterprotesters involved in the April 30 attack, which the police allowed to continue for several hours without intervening.