One thing everyone agrees on, is Bamber made the scratch marks on the bathroom window. With his hack saw.
Supporters will always say this was because a 24 year man apparently left his passport at mummies and daddies. Then apparently decided it would be easier to get a hack saw and climb through a window to get it. Rather than walk through a front door.
The prosecution have a very very strong counter argument. Which the judge asked the jury to consider.