First, in order to accurately understand the events, one must put them into the context of the time. The Ural Soviet decided that the continued existence of the Imperial Family gave the White Army and its supporters and allies too much hope and support and so they decided to murder them all, but to cover it up. It was a bit of disinformation really, because they were also scared that if the murders were public knowledge that the Whites would then seem them as martyrs and seek revenge. So, the idea was for them to totally disappear so that no one would really know what had happened to them (this worked).
OK, lets look at what we know: No question 12 people went into a small room. More armed men chosen especially for their hatred of the Imperial Family took turns shooting them. No question here either. We know several survived initally, and were finished off, at least to the satisfaction of the executioners. Again no question so far. Yurovsky testified that he personally shot each survivor in the head at least twice. We may choose not to believe this. I see no reason not to believe him however as there is no motivation for him to lie about this point. Valuables were found, bodies were searched and handled. Again, no question.
An important point to remember is that everyone involved in the murder at this point, every eyewitness, was convinced they were all dead.
A truck was stationed at the front door of the house. We have the requisition record. Guards were posted in the street to make sure no one came by. We have the posting records and their testimony. Strekotin and Yakimov among others. We also have the driver of the truck sitting in or standing next to it. A six passenger car, an Overland, was delivered to the front door as well, we have the records, and its driver was sent away and told not to come back.
Now. Every single eyewitness testimony says the same thing: Each corpse was removed and placed onto the truck. Again, each person handling each corpse and putting them onto a stretecher and carrying them to the truck is still convinced they are all dead. No one says they actually counted them at this point, BUT, we also know that another detachment of guards who were not present in the house at the time of the murders was sent in immediately afterward to physically clean up the basement of the blood and other remains of the murders. We have their assignment posting logs and their testimony.
So: If there are guards and a truck driven outside in the street to make sure no one comes along, everyone admits that every corpse was put on the truck, and there was no one left in the basement when the guards went down to clean up. WHERE could any of the bodies have gone? There was no time when they were unattended between the shootings and the truck leaving. So, everyone must be and is still accounted for and on that truck.
Now, testimony at the mine says that the bodies were indeed counted. We can disregard this if you wish, but bear one important thing in mind. In the Russian Orthodox religion, an "uncorrupted body" is required for that person to be a saint. We know from testimony that it was agreed that each body was to be stripped of their remaining clothing and be disfigured so that they could not recieve Sainthood rites in the Church and they were making sure that each "candidate" was accounted for. We have an eyewitness who says specifically he saw Alexei at this point. Also, who would remove a body from the truck at this point and how could they have carried it off unnoticed prior to the disfigurements and stripping off the remaining clothes from the bodies (to burn the clothes and hide the evidence), and where would they have taken it? Where would they have hidden it? How could they have tended medically and physically to them? How could this be kept secret? Remember, this is in a boggy wet desolate forest miles out of town. We know though that physically speaking, this is the only point in what is known of the chain of events where anyone "might" have survived and escaped. What happened later really almost doesn't matter.
Now, we must also be remembered that the Bolsheviks were not convinced that they might win. So, they were also motivated out of fear that IF anyone survived or any evidence of their murdering the Imperial Family was found later, they could be tried and convicted for their actions. This is an important point.
How much more physical evidence can we hope to have?
Yes, everyone has an opinion, but some are more informed than others. How much research have you done to support your contention that more evidence is required? Please let us know your sources.