Thank you Notsure.
Well all the evidence shows Sheila did not commit the massacre. At the time this evidence had not been processed. The relatives would have been jumping the gun somewhat attempting to fabricate the silencer without knowing anything.
Unfortunately it was Sheila's blood. My question is did they have access to it. My view is the relatives did not have access to it. There is also no way they would know what Sheila's blood type was.
Don't know how saying "the silencer wasn't used" answers the questions about back splatter, the rifle lenght & the relatives expertly inserting blood. The evidence says the silencer was used. That will never change. The questions are asking if the relatives were able to fabricate the silencer.
It seems you are saying the relatives were prepared to take the risk that the crime scene photos did not include the aga. That was a big risk. If they already had Sheila's blood they didn't need to take it.