Officer Michael Lafrano spotted a suspicious vehicle outside the post office on River Road around 1:30 a.m. Monday and went to investigate, Detective Lt. Kevin Van Saders said.
Seeing one of the men tampering with the dropbox, Lafrano called for backups, Van Saders said Tuesday.
The trio tried to flee when they saw the officer, but Sgt. Scott Petrie and Officer Vincent Siekierski arrived and assisted Lafrano into taking them all into custody, he said.
They were identified as Charles Ward, 26, and Ronald Jaquez, 24, from the Bronx and Roquelin Paulino, 21, of New York.
All remained held Tuesday in the Bergen County Jail pending detention hearings on charges of trafficking personal identifying information, as well as several counts of burglary, theft, conspiracy, fencing and possession of stolen property, burglary tools and drug paraphernalia.
Police urged anyone who used the dropbox outside the New Milford Post Office on Saturday or Sunday to verify that their mail was received by the recipient.
They advised those with problems to contact borough Police Officer Keith Wester at (201) 967-5878.
Click here to follow Daily Voice Jersey City and receive free news updates.