A really melee focused investigator? Take advantage of that STR and CON while using the INT?
Good will and Reflex Saves will help compensate the low dex and Wis.
Take Sacred Tattoo or Toothy instead of ferocity.
Take HP for the Favored Class Bonus - you will need them.
Take Mutagen as your Investigator Talent (3ed), at 5th Quick Study and Sickening Strike at 7th.
Use a Great Axe
Feats: WF Great Axe, Dazzling Display (Great Axe)
Skills- Intimidate, Perception, Alchemy, Disable Device, UMD, Stealth, assorted Knowledges...
next level you get Focused Combat - which gets pretty close to keeping up with the fighter for melee combat.
Your tactics are intimidation (dazzling display) and poisoned weapons to weaken your enemies, then finish with a greataxe... Use Extracts to buff yourself as appropriate (suggestions - Shield, Long Arm).