We’ve been following the case of Collin McKenzie-Gude, 18, of Bethesda since his arrest last week on charges of making and exploding pipe bombs and illegally possessing firearms. At first glance, the circumstantial evidence that’s been piling up paints a pretty weird picture. Here’s what’s happened so far: On Tuesday, July 29, Montgomery County investigators acted on a tip from a concerned citizen and searched the Gude family home on the 6300 block of Rockhurst…