Actually I don't have to assume it. It is entirely possible there where some traces of the climb, and ILE just missed them. Such educated guess is confirmed by various other traces ILE missed and by the fact that there is no proof of any extensive search for such traces.
I'm entirely aware, that the defense is in a serious disadvantage when dealing with such witnesses. I'm not sure the defense have to prove something, it can always state there is no proof the witness is right. After all the burden of proof should be quite high, we're dealing with serious accusations.
But I'm not in court, so I can base my position on reason, not courtroom tactics, and I (hopefully) don't have to be afraid of slander charges.
So I just make an educated guess, that although some witness stated there was no traces it is still entirely possible that Rudy climbed that wall anyway.
Massei's first-rate "reasoning" regarding the ground underneath Filomena's window is on pp50-51 of the translated report. Firstly, it's evident that the court seems to rely (somewhat bizarrely) upon the testimony of Filomena herself, and her boyfriend Marco on the issue of the ground conditions. Furthermore, the Massei report only makes reference to the verbal/written testimony of forensic officer Gioia Brocci (and her assistant) regarding the condition of the wall. There is no discussion whatsoever of any photographs that might have been produced in court to show, close-up, the exact condition of the ground and the wall on 2-3 November. There's no apparent discussion of recorded meteorological conditions in Perugia in the last week of October and 1st November. Given that a major plank of the prosecution's case was that the break-in was staged, they (and the police) appear to have fallen far short in attempting to demonstrate that any assailant would have had to leave marks in the ground and upon the wall. And given that the prosecution has the burden of proof, I'd say that they failed to offer sufficient proof that the break-in was staged, in regard to the condition of the ground and the wall.
Secondly, Massei draws these awesome conclusions about the glass from the window (p51):
"The climber, in leaning his hands and then his feet or knees on the windowsill, would have caused at least some piece of glass to fall, or at least would have been obliged to shift some pieces of glass in order to avoid being wounded by them. Instead, no piece of glass was found under the window, and no sign of any wound was seen on the pieces of glass found in Romanelli's room."
In other words Massei seems supremely confident that anyone breaking in
would have (not
could have) caused some glass to fall to the outside - for logic that he doesn't care to elaborate upon. Massei also seems very confident that had the assailant instead clambered over the broken glass, he would necessarily have been injured in the process. He appears to be unfamiliar with the concept of gloves and a heavy coat.
Here's his second piece of stellar reasoning regarding the lack of glass on the ground below the window (p51):
"It can moreover be observed that the presence of many pieces of glass on the outside part of the windowsill increases the probability of finding some small pieces of glass on the ground underneath, since there seems to be no reason that so many pieces of glass would all stop just at the edge of the windowsill without any of them flying beyond the edge and falling down to the garden below."
So here, Massei is saying in his inimitable style that there's "no reason" why there should be pieces of glass on the outer windowsill, yet none on the ground. He seems to believe that the glass found on the sill must have been flying backwards with a significant velocity, from his use of the phrase "...would all stop....without flying beyond the edge". In reality, of course, the strong likelihood is that the pieces of glass on the sill had simply fallen vertically down from the pane follwing the impact of the rock, and had merely toppled over upon landing on the sill, to rest in the position on the sill in which they were found. In other words, these pieces of glass were never "flying" backwards to any extent whatsoever.