1) The window wasn't wide enough to pass Madeleine thru, unless she were held in a standing up type position.
2) If that were the case then she was either drugged or screaming her head off ... and she would have been heard . Also she appeared asleep (or drugged) when carried by Bundleman
3) We are told there were no fibres, dirt or scratches found around the window frame or sill, so no-one went thru.
4) The likelyhood of Kates prints being the only ones on the window frame are zero. Cos the first thing everyone connected to The Mccanns would have done, would have been to grab onto the window frame and lean out as far as they could ... looking left, right and down.
Everyone would have done that! Excuse my language, but there was a PJ b**ls-up there.
Kates prints alone ... what nonsense! Sounds like some-one is fitting her up. But then the PJ wouldn't do anything like that, would they?
5) The window was not really wide enough for a man to get thru and it was reasonably high off the ground from the outside. With an extremely thin man, it could be done, but the man would have had to have stood or kneeled on the sill ... no marks there! ... and what a struggle!
I am fairly competent at figure drawing and body proportions.
Having seen the height of that window sill from outside, I can tell you with confidence that NO MAN could have got into 5A via that window without his crotch being severely damaged.
Physically, his legs would not have been long enough. Remember the depth of the sill. Even if the walls are only a minimal thickness, he will have had to arch his privates over at least a sill of about a foot ... and at thigh level ... come on!
Gawd think of the pain he would be in! LOL! ... and there would be fingerprints everywhere!
So alternatively, he was skinny and stood/kneeled on the sill. ... But as apparently there were no marks, we can rule that one out.
Nothing human went thru that window. It is a Red Herring!
Only my opinion, but lots of pointers. Heri on Myths has another opinion, but there are a lot of BUTS with that ... again only my opinion.
The FRONT DOOR was used both in and out, almost certainly !