Dark Stories: Midnight Killer Walkthrough Page 4:
He will tell you that the murderer lives across the creek.
Talk to him to get some wolfs root.
Double-tap the roots in your inventory to use it on yourself.
Cross the creek.
Go into the house and talk to the man.
He will invite you into his house. Exit the dialogue box and enter the house.
Go into the bathroom in front of you.
Use the plaster shoeprint you have on the boots next to the toilet. It will match the murderer's shoe and you will gather some evidence.
Go out and right and you'll see 4 more doors.