random neighbour looks out, see's robber going through window, risk, but its not that long a space of time. robber leaves and 2 seconds later neighbour looks, see's window missing, knows they are away, calls police, happen to have a car cruising by the road, see's a dodgey guy in a van with a mask on. anything to increase time between get away and finding out there was a crime = better. replacing a window which could take seconds can hide evidence of a crime so its completely plausible a burglar would replace the window. of course, if an alarm is going off, there seems little point, what trips the alarm, ask the neighbours about the alarm and if they heard it. maybe the landlord did it.
as others have said, why would someone he knows replace the window? theres not a single reason that someone he knows would replace the window, over someone he doesn't.
also, why would he take a screen, and not the xbox which is clearly sellable, easily, and the hard drives would have been easy to take. break in, take one thing, instead of 4, seems really stupid.