The U.S. Justice Department shut down Bal Harbour’s celebrated federal forfeiture program and ordered the police to return more than $4 million, slapping the agency with crushing sanctions for tapping into drug money to pay for first-class flights, luxury car rentals, and payments to informants across the country

After years of seizing millions from criminals, Bal Harbour’s vice squad is now banned from the federal program that allowed the village police for years to seize cars, boats, and cash — and to keep a cut of the proceeds.

In a scathing letter to Police Chief Thomas Hunker, federal agents are demanding the prompt surrender of the millions reeled in last year by a team that operates from a police trailer just blocks from the opulent Bal Harbour Shops.

For years, the small coastal town known for speed traps became one of the most successful in Florida, with plainclothes cops jetting across the nation toting bags stuffed with cash from investigations that had no connection to Bal Harbour — and making few arrests.

The findings, released on Tuesday, were also sent to Mayor Jean Rosenfield, who could not be reached for a comment.

The action by the DOJ’s criminal division comes after a lengthy investigation that began last year with an audit and escalated into a deep probe that turned up a host of problems, including questionable expenses, hundreds of thousands paid to snitches, and missing records.

Neither Hunker, 61, who founded the unit after becoming chief in 2003, nor Sgt. Paul Deitado, supervisor of the squad, returned calls on Tuesday for comments.

One former prosecutor who ran the South Florida Money Laundering Strike Force said he was stunned by the development.

“Bal Harbour is going to have to answer for their transgressions,” said David Macey, a former Miami-Dade assistant state attorney who specialized in forfeitures.

“I’ve never read any correspondence to a law enforcement agency threatening the entire agency with penalties and criminal sanctions.”

Former Bal Harbour Chief Alfred Treppeda, now village manager, said the village council will meet for a special session on Thursday to talk about the troubled program, now under criminal investigation.

Treppeda declined to discuss the sanctions — among the toughest against any agency in the country. “We haven’t really had a chance to talk to the Department of Justice yet,’’ he said.

The Miami Herald reported on Sunday that the police department — a small-town force that mostly writes traffic tickets — has doled out hundreds of thousands to snitches, ran up $23,704 in one month for cross-country trips with first-class flights and Cadillac and Lincoln Town Car rentals, and misspent seized funds on police salaries and benefits.

The Herald found that two of the police officers were not even based in the village — but hundreds of miles away in Southern California and Florida’s west coast. Their roles: to manage the snitches.

In less than four years, the unit paid $624,558 to the informants for tipping off cops to lucrative busts in New York, New Jersey, California, and other states, the newspaper found.

On Tuesday, The Herald sued Bal Harbour over the village’s continued refusal to turn over all of the unit’s spending records.