His claim that the relatives fabricated the silencer would carry less weight if it was next to Sheila. If they found it later.
He would have to agree it was used & Vanezis would have already said Sheila recieved contact shot/s.
Although likely it was taken away as a crime scene exhibit. May have taken a few days or weeks but the combination of rifle length, contact shots & Sheila's blood would have seen EP come to the right conclusion. Stan was determined.