There's a raid going on -- still as we write -- at the Soho offices of one of the city's biggest housing developers. Since seven this morning, blue-jacketed agents of the Manhattan District Attorney's office have been hard at work, hauling boxes of records from the offices of Atlantic Development Group at 155 Avenue of the Americas near Spring Street.

"It's part of a long-term investigation," said one top prober who declined to give details. "We're about half way through so far."

Atlantic's principals are Peter Fine and Marc Altheim who have made themselves into some of the city's most influential -- and politically generous -- developers. Atlantic has developed more than 20 projects -- many of them publicly subsidized.

Its biggest current effort is the huge 700-unit project called "Boricua Village" at Third Avenue and 163rd Street in the Bronx where Atlantic is developing a new "vertical campus" for Boricua College. That's the same project that was cited in a recent Daily News series concerning ex-Bronx Borough President Adolfo Carrion who managed to hire the project's architect to work on his City Island home -- and never get billed for the work until the News started asking questions.

Atlantic has also been a virtual cash machine in recent years for Bronx politicians and others. City campaign finance records show that Atlantic and its officers and family members have anteed up more than $160,000 to city pols in the past four years. Among those on the receiving end are Carrion, who took in $29,000 before snagging a policy job with the Obama White House; city council member and comptroller candidate Melinda Katz (who chairs the council's land use committee), and Bronx council member Joel Rivera with some $15,000 in contributions from the Atlantic team.

The developer has also tangled with city construction unions -- especially the carpenters -- for using nonunion labor on its projects. Atlantic recently won a court order barring pickets from another project it has underway, this one just down the street from Voice offices at the Bowery and East 4th Street where a large hole in the ground is threatening to become luxury apartments at some point. A union picketer told Runnin' Scared: "All they do is use immigrant workers who get no benefits."

Calls to Atlantic have so far not been returned. But we know how that is. Investigators like to turn off the phones while raids are underway.