Four teenagers were arrested and charged with vandalizing a Jewish cemetery where hundreds of headstones were toppled, authorities said Thursday.

The damage did not appear to be a bias crime, they said.

About 500 headstones at the Poile Zedek Cemetery were toppled or broken apart the evening of Jan. 4. Three nights earlier, about 20 headstones were damaged.

On Wednesday night, authorities arrested four New Brunswick boys ages 15 to 17. Three were charged in both incidents and the fourth with participating only in the Jan. 4 vandalism, authorities said.

"The facts as presently known do not indicate that the damage caused was an attempt to intimidate, target or harm the Jewish community," Middlesex County Prosecutor Bruce Kaplan and New Brunswick Police Deputy Director Anthony Caputo said in a statement Thursday.

The four were sent to the Middlesex County Juvenile Detention facility, charged with juvenile delinquency for acts equivalent to the adult crimes of desecration of venerated objects, criminal mischief and conspiracy, they said.

Rabbi Abraham Mykoff of the Poile Zedek Congregation said about three-quarters of the tombstones in the cemetery had been damaged, but none had been defaced with swastikas or other anti-Semitic signs. Some of the monuments weighed as much as 3,000 pounds, he said.

"It was done methodically, row by row and section by section," he said Thursday. "It took hours." Earlier, he had called it a "malicious intent to destroy a Jewish cemetery."

The Jewish Federation of Greater Middlesex County is setting up a restoration fund, he said.