After being attacked by the Bogeyman in the monatery morgue, you are knocked out and wake up in an unknown location outside. Start walking forward. Suddenly you hear a voice, "Help me daddy please". There is a shovel on the ground if you need a weapon. Go down some stairs and go towards the lake. You hear Charlie calling out for your help again. You assure him you are coming. Keep going down the stairs, grab the hammer if you want, and run to the lake. You see Charlie in the lake. Run to him. Suddenly the Bogeyman emerges from the lake. This is a boss fight.
Bogeyman Lake Fight
If you have a gun and ammo, now is a good time to use it. Shoot the Bogeyman from a distance, and avoid his shockwaves. If you do not have an adequate supply of ammunition, then this fight is going to be a lot harder. Perform a hit and run technique, closing in after each shock wave, striking the Bogeyman with your weapon, and quickly retreating to a safe distance. If your weapon breaks during this combat sequence, there are a few more scattered on the ground, such as a crowbar in the center.
Once you have weakened the Bogeyman enough, he gets on his knees and prepares an area of effect attack. When the Bogeyman kneels on the ground, IMMDEDIATELY run towards him and strike him in melee. See the image below for the exact moment to charge him:
Strike the Bogeyman a few times. You will take his hammer from him and use it against him. Then you wake up at the morgue again. Where the Bogeyman was, instead there is a body with changing faces. Charlie is there. He tells you that you killed him you killed the Bogeyman. You tell Charlie that it doesn't matter, it didn't bring him back, nothing can bring him back. Charlie tells you that it is not your fault. The body disappears, and you grab the DJ Bobby Rick's keychain labeled "Freedom" for the DJ's boat. Charlie has also disappeared. You receive the achievement "Broken Cycle" for having defeated the Bogeyman at the lake.
Now that you have the Boat Key, it is time to leave St. Maria's Monastery. There is a crack on the morgue's wall, taking you to the sewers. Go through the sewer tunnels, climb the ladder at the end, and emerge outside, between Chastain Heights and Pleasant River.