Consolidated Edison said it received a subpoena Wednesday from Attorney General Eric Schneiderman and is cooperating with his investigation into Con Ed's preparation and response to Sandy.
An official familiar with the investigation said the Long Island Power Authority also received a subpoena Wednesday.
The official said Schneiderman seeks plans and performance records on restoring power, communicating with customers without power and other aspects of the utility's response to the storm.
The storm sapped electricity for more than 2 million New York customers.
"We are cooperating with the attorney general's request," Con Ed stated. "We look forward to reviewing the company's storm preparations and response with the Attorney General and all interested parties."
There was no immediate response to a request for comment placed with LIPA.
On Tuesday, LIPA COO Mike Hervey resigned after 12 years. A permanent CEO slot and several board seats have been vacant for months awaiting appointment by Gov. Andrew Cuomo. Cuomo, however, has said LIPA is simply an outdated political entity he wants to overhaul and that National Grid, contracted by LIPA, is responsible for providing power to Long Island.
A spokeswoman for Scheneiderman declined comment.
The probe is separate from a commission created by Cuomo to investigate utilities involved in Sandy.
Schneiderman plans a broad look at the preparation and response to Sandy and a nor'easter that followed, the official said. The Attorney General's Office has investigation powers and the power to enforce state laws including public service and consumer protection laws, which could provide greater latitude than the Moreland Commission.
The Moreland Act Commission created by Cuomo can investigate and refer evidence to a local district attorney or the Attorney General's Office. The commission could also issue a report recommending legislative changes.
The official said Schneiderman is specifically looking into areas that include efforts to restore power, how well the entity communicated with customers without power, power line maintenance and the trimming of tree limbs near power lines and the loss of power distribution equipment and service at substations.