Newspaper articles typically follow an informative format. The killing of the old man and the confession of his roommate would have been quite a sensational story! You will want to include actual quotations from the narrator, because of course it will be more interesting with his voice added. A newspaper article should then give details of Who, What, When, Where, Why and How.
The main players involved were the narrator and the old man. Since the narrator does not have a name, you could pretend that his name is being kept secret due to the criminal proceedings. You can call him the Suspect. The old man is the Victim, or the one who was murdered. We don’t know much about him, but he was the Suspect’s roommate and had some money.
What, When and Where
What happened was that the Victim was found murdered last night in the house he shared with his roommate. (It would be best to say last night, since you are writing the newspaper article). A scream was reported by neighbors sometime in the night, and police investigated. The suspect showed them around, and had them sit in the Victim’s room. The Suspect then confessed to police that he had in fact murdered the Old Man (as he called the victim) and hidden him in the floorboards.
Here is a good place for a quote from the Suspect:
“Villains!” I shrieked, “dissemble no more! I admit the deed!—tear up the planks! here, here!—It is the beating of his hideous heart!”
This would be the Suspect telling the reporter in an interview. It would be quite a juicy quote!
I suppose your readers would be most interested to know why. This is your main purpose for interviewing the Suspect, to find out. He would tell you himself that he is not crazy.
He had never wronged me. He had never given me insult. … I think it was his eye! yes, it was this! He had the eye of a vulture—…
At this point, you could interject some commentary about how the Suspect may not be in his right mind, because the Motive (reason for the murder) was apparently the Victim’s eye.
Your readers will of course want to know all the gory details. It appears that the Suspect threw a bed on top of the Victim, and then dismembered the body and hid it under the floorboards. You might get the Suspect talking, and ask him why there was no blood found at the scene.
There was nothing to wash out—no stain of any kind—no blood-spot whatever. I had been too wary for that. A tub had caught all—ha! ha!
So he cleverly hid the body, but ended up confessing. Why? As the Suspect told you, he had hallucinations that he could still hear the Victim’s heart beating from under the floor—even though he was dead.