Robin committed suicide by holding the rifle against his head with the silencer attached and without leaving fingerprints


While the Defence demonstrated that this is physically possible, the likelihood of it is remote.  There would be so many other easier options for Robin to use, such as:

  1. placing the rifle in his mouth or
  2. at least removing the silencer first.  It is assumed that if he is capable of fixing a misfire while also fighting with Stephen then he is familiar enough with the gun to know how to remove the silencer.  Also if he had the time to prepare himself by changing his clothes then he would have the time to make his final moment a lot easier to implement.

The ignomy of failing your own suicide would be very hard to live with and so you would expect someone who has so carefully killed each member of the family in what was a well prepared mass murder would take care in ensuring a 100% successful suicide by employing the most effective means possible.

In addition to this the gun did not have Robin's fingerprints on it.  The result is a low probability for this event occurring.