The 'Scooby Doo' Approach -- It's always a man and a mask!
Give them a perfectly plausible explanation...
Make up some 13 foot high sasquatch,
mount it on an ATV? remote controll or autonomous mobile base
and leave it in a nearby garage direct it near a patrol to encounter
What they should conclude/Clues should point to:
Who? -- Parties unknown, suspected college prank or U-tube
What? -- Prank gone wrong
Why? Alcohol induced inspiration for u-tube post
Gremlin Squad -- Murphy's 'Little Angels'
-- Fill aircraft oxygen tanks with nitrous oxide
-- Switch fuel labels - MOGAS for Diesel and vice versa
-- Crossover Cable rather than a Pass-through cable.
-- Expired rations
-- Expired batteries.
-- Wrong crypto issued/used
-- Interchangable parts that interchange don't in the spares kits
-- Wrong parts shipped.
-- Wrong forms used.
-- Incorrectly filled out forms.
-- Incorrect version of the form.
-- Incombatible firmware version
-- Incorrect password Entered
-- Blown Fuse
-- Manufacurer Defect (1 in 25 unit failure rate)
Intrusion or Disruption of Command and Control network
Friendly Fire Incidents?