I'm sticking with Vatman Jr.

The four days missing was Clark being held [via kryptonite/no sun] but not killed yet. He managed to escape and then NotReallySuperman killed him.

Someone needs to get in touch with Martha and Jonathan. Like now. Or maybe Wayne Irig or Maisie or someone knows something they shouldn't. Or heck - Perry's not editor because he can yodel after all...

Carol