Prime requisite: INT
Hit dice: D4
Advances as: Thief
Attacks as: Thief
Saves as: Thief
Weapons permitted: As thief
Armour permitted: Leather
Magical items permitted: Any permitted to thieves
There was only really one conclusion to be drawn, and it had been obvious all along. He reached for the scroll to write down his findings about the church of the Evening Star, and their cult activities.
More at home in the city than in the dungeon, the investigator is an expert in the human mind, and in finding and combining clues to draw conclusions from them.
Empathy: Investigators must develop a keen sense of other people and their patterns. They may detect alignment as per the spell once per day, increasing to twice at level 5, and three at level 10.
Determine motives: If a henchman or hireling has secret motivations, or is a spy or traitor, the DM should roll a D6 every day. On a 1, the investigator has stumbled across something that indicates this to him. The exact nature will not be known, but the investigator will know whether it's hostile, neutral or benign.
Sometimes you have to do it yourself: Investigators may move silent and hide in shadows as a thief of the same character level. If they are stalking or shadowing a target for surveillance they may add +10% to their chance of success.
Keen eye for detail: Their skills extend to dungeon pursuits as well. Due to having a good eye for small details, an investigator can detect traps, hidden doors and listen for noise, succeeding on a D6 roll of 1-3.
You can't fool me: Whenever an NPC tells a lie or omits the truth, the DM should secretly roll a D6. On a 1-2, the investigator will suspect he is being misled though he won't know the details.