Your investigation will lead you to the old lumber mill, a sprawling industrial area filled with machinery and shadowy corners. This area introduces the 'Poltergeist' Taken, which can possess objects and hurl them at you. Use your flashlight to burn the darkness from these possessed objects, rendering them harmless. The Flare Gun, if you've found it, is excellent for clearing groups of Taken in tight spaces.
Navigate the mill carefully, using the elevated walkways and cover to your advantage. There are several generators that, when activated, will illuminate sections of the mill, creating temporary safe zones and revealing hidden paths. Be wary of ambushes from above or behind machinery. The lumber mill is also a good place to find Shotgun ammunition, which is highly effective against unarmored Taken at close range.