Final answer:
The type of irony in this situation is dramatic irony. The audience knows that the killer is in the house, but the character entering the house is unaware of this fact.
Step-by-step explanation:
The type of irony in this situation is dramatic irony. Dramatic irony occurs when the audience is aware of something that the character(s) in the story are not. In this case, the audience knows that the killer is in the house, but the character entering the house is unaware of this fact.