Lots of things, Drum bearings, some thing trapped under drum It is going to be some thing rubbing on something else, to state the obvious. But it could be lots of things, 1st thing is to check around the drum, empty. turn the drum, does it squeek, Does it move up/down side/side, without any resistance. Any slight resistance would cause the squeek, but would also say bearings, that is if you can move it, even slightly. other than that, check around the drum as much as you can, any obstruction. Not missing a wire from a bra are you, that is one of the main problems in washers etc. Find nothing, you will have to get someone in. Could be nothing, But, If you cannot find it what else.
SD, November 2012