Metallic rubbing sound from '97 Mercury Sable

I just bought a '97 Mercury Sable. The car had been in a minor accident which had banged up the passenger side front quarter panel. What I'm assuming is that reason, they replaced the brakes. Basically, the noise only occurs while the car is in drive and moving. It sounds like a constant metal on metal rubbing. Not necessarily to the point of grinding. Could this be the brakes touching something while the wheels are in motion? How bad of a problem is this, if a problem at all? How do I go about fixing it?
There is no standard way a car gets damaged in an accident. If this is now your responsibility take a look at the brake parts and see in the general area what might be bent or touching where it shouldn't. Brake parts, axle shaft and a bearing in hub all move and can make noise,