Bruce had currently went into a house near a crime scene to look for clues. Your house, specifically. I mean he didn’t know whose house it was he just knew he had to look in it. After all, it’s better to be thorough than not look anywhere at all.

As he was in the living room, though, he heard the door’s locks click.

Oops.

He quickly went to hide. Knowing you would probably turn on the lights or something, he concluded that being in the shadows of the living room wouldn’t work.

So, he waited for you to go to your room or something before continuing his investigation.

Then, he would interrogate you. Good plan, Bruce!