You weren't trying to be particularly sneaky when you realized that the police were on their way to your home, but you also didn't want to get into trouble. A friend at your home had a warrant out for their arrest, but you took them in and hid them. Now, the police are on their way after getting a tip.
You decide to hide your friend inside, but when the police turn up with a warrant and search your home, they discover that you lied about your friend not being there. Now, you're being charged with obstructing justice for lying to the investigators.