David prefers to suggest the relatives -
Dipped their hands into a bucket of cold water.
Pulled out some soaking wet underwear which may have had some diluted blood on.
Waited until this underwear dried.
Expertly transferred any miniscule dried blood embedded into underwear into the silencer baffles.
Oh, and then scratched the aga.
As mentioned, David is also suggesting the relatives guessed the following & hoped for the best -
Contact shots during the massacre.
Liklihood of back splatter with that rifle.
Blood already on rifle nozzle.
Photos of aga.
Lenght of rifle with silencer.
Lenght of Sheila's arms.
Other evidence showing guilt/innocence.
Police checks already carried out on silencers.
Where to get Sheila's blood.
How to insert Sheila's blood.
If unable to get Sheila's blood, what was her blood type.
Would someone else's blood be enough.
How to effectivly scrape the aga to replicate a scrape during a random fight.
Possibility of a successful silencer frame securing a conviction.
Punishment if convicted of a attempting to frame a man of murdering 5 people.