The old man is getting smothered with a blanket until he is dead.
The police showed up because of a screaming complaint.
The old man is sleeping and getting stalked and little does he know that he is being watched while he sleeps and he is about to be killed. He hears noises every once in a while and wakes up and is kind of scared but he thinks its nothing.
After hours of waiting and staying still so he doesn't get caught he finally gets into the room and pulls the old man off the bed and smothers his head with a blanket and as the old man is screaming he has no way out, eventually he died while getting smothered.
People across the street had heard the screams and called the police. The police showed up to the house the next day. The man led them into the room that he had killed the old man in. he put chairs for them across from him and his chair was over the dead body that he cut up and put under the floor. Once they kept talking he heard a heart beat getting louder and louder and he finally just confessed that he had killed the old man.