By now, if you have read all my posts, you are very likely dying to know, WHAT DOES ALL THIS HAVE TO DO WITH RUDOLF LACHER?
I will not hesitate any longer.
First of all, he was a real person; if he has any relatives, they carry with them the burden of the accusation of murder, a burden I hope to dispel, or at least cast all that should be necessary to exonorate him: REASONABLE DOUBT.
RUDOLF LACHER
Here is his photo:

A good looking chap. The facts: Austrian prisoner of war. "Joined the Habsburg Army in 1914 and was sent to the Carpathian Front. In 1915 captured by Russian troops in Galicia and sent to labor camp in Urals. After the revolution, 'allowed to do work... provided I had authorization'... secured a job in Verkh-Isetsk factory, largely on strength of linguistic talents... speaking German and Russian... acted as official interpreter... rising quickly through the ranks of his comrades until he came to Yurovsky's notice. (FOTR, p.270)
THE ALIBI
He claimed on the night of the murders "Yurovsky had locked him into his room at midnight... insisted he had watched through the keyhole of his door as the victims passed, noting that all of the grand duchesses were sobbing as they descended the staircase. Later, he said, after a number of shots, he climbed on his bed and peered out of the window, counting 'eleven bloody bundles' as they were loaded into the waiting Fiat. (p.591)
THE CASE AGAINST RUDOLF LACHER
"Lacher's room, directly beneath Yurovsky's office, had one small window, with double panes of glass, sunk deeply into the two-foot-thick stone wall; between it and the courtyard gate, into which Lyukhanov had backed the Fiat, the first palisade was attached to the eastern facade of the Ipatiev House and, beyond this, the main stairs, with high conrete piers on either side, further obscuring the view and eliminating any possibilitly that Lacher could have seen what he claimed." (p.591)
The ONLY other evidence is "inferential": "Netrebin, who recalled that, of his comrades, only Lepa and Verhas did not participate in the shooting." (p.591)
ANALYSIS
Let us look at the case, point by point. We need to first see where this window and room were located.


You can see that photos of this window are hard to come by; nevertheless while the stairs obscure a small portion of the line of site, virtually all activity in this area in front of the house, once enclosed by a palisade, is visible from this window.
"Wait a moment!" says the prosecution. "What about the first palisade! Did you not read the testimony? "the first palisade was attached to the eastern facade of the Ipatiev House" thus obscuring his view.
"Have a closer look," says the defense. "The first palisade meets the wall precisely between the commandant's windows, splitting Lacher's window in two. He could, in fact, see quite clearly virtually any activity in this outer courtyard."
Here is a muddy photo of the first palisade (this too is often misplaced in models). You can see (barely) the visible half of the window. Look closely, it is indeed there. And more importantly, by viewing the placement of the fence directly between of the upper two windows, based on the location of the window in other posts one can better visualize the 50/50 split.

"But if the lorry was in the internal courtyard..." objects the prosecution weakly.
"No!" says the defense. "We have spent two previous posts and several hours proving otherwise!"
Recall the approximate location of the lorry, based on evidence and testimony:

CONCLUSION
Observe, if you will, his line of sight from said location:

"THEREFORE," thunders the defense, "Rudolf Lacher could very well have witnessed the loading of bodies into the lorry. Given the evidence surrounding the true location of the lorry, it is certainly far from IMPOSSIBLE he did not, casting REASONABLE DOUBT to his involvement in the shooting."
The judge, aroused from his slumber, looks about dazedly and claps the gavel. "Given the new evidence on the location of the Fiat lorry," he states judiciously (for isn't that judges do), gazing down at Rudolf Lacher. "You sir, are hereby free to go!"