Investigators for New York Attorney General Eric Schneiderman Wednesday raided the headquarters of a Long Island firm that allegedly falsified damage assessments for homes flooded by Sandy.

The search followed a ruling last year by a federal judge who determined engineers from the Uniondale-based GEB HiRise and other companies may have altered reports to suggest that homes were damaged before Sandy. That could cut insurance payouts in half.

The judge ordered documents to be turned over, but lawyers for the homeowners said some of the materials appears to be missing.

"And our reason for that belief is that some of the documents we have gotten make reference to other documents that we don't have," Tom Maligno, with the Disaster Law Clinic at Touro Law School, which is assisting Sandy victims.

Executives for HiRise said they are cooperating with investigators.

"HiRise has a 15-year history of ethical business practices," Chief Executive Joe Celentano said in a statement.