Hello Bricktop.
Dear BrickTop,
I believe that Dr Dark is correct. Nevertheless, Rex will issue final judgement upon their return, but the rules appear quite clear in this regard.
Ultimately this is an internal faction issue and it is best to speak about to people to see if anything in the faction has taken anything or misplaced it elsewhere first. It has only been a few hours since it happened I can tell and therefore someone may have accidentally logged off with it or some such incident.
Either way be sure to ask about the faction, I know we had disappearing pentaxid in PKA in 5.0 but never found the culprit.
Good luck,
Best regards,
Wise.