Fitchburg (AP)  -- Furious Fitchburg residents want to know why it took so long to fully restore power after the Dec. 12 ice storm.

So do state regulators.

As some people in Fitchburg and three other towns spent a 12th day in the dark, the state Department of Public Utilities announced it would hold public hearings as it investigates how Unitil and other utilities responded to the storm.

As of last night, some 300 Unitel customers were without power in Fitchburg. Unitil senior vice president George Gantz said he expected all customers except for those in a few "spotty patches" to have their power restored by last night.

Fitchburg Mayor Lisa Wong closed the city's emergency operations center and said last night would be the final night a shelter at the senior center would operate.

National Guardsmen who'd been helping with recovery efforts since the storm have also left the city. As of last night, some 300 Unitel customers were without power in Fitchburg.