How does Roald Dahl use dramatic irony to engage his readers? What effect (s) does this irony have on a readers' experience?

Roald Dahl used dramatic irony to create a suspenseful yet intriguing scene for the readers. It captures our attention and did it so well as to entice us to know what the ending will bring.

This dramatic irony makes the readers so engrossed in anticipation, eagerly awaiting the moment the crime may be solved.

Explanation:

In his story "Lamb to the Slaughter", Roald Dahl used dramatic irony to reveal the true events and to maintain the suspense. The dramatic irony is seen when the audience knows the happenings in the story but the characters have no idea about it.

Likewise, the police officers who came to investigate the death of their fellow detective Patrick Maloney who had been killed in his own home. As readers, we know that he was killed by his wife Mary with a "leg of lamb" that she was planning to make for dinner. Then, when the officers accepted to have dinner with their dead colleague's wife, they had the very same murder weapon for dinner, the "piece of evidence" that they need to prove the murder. The best scene is when they admitted the weapon may be "right under our very noses", which it literally is, on their plates.

This dramatic irony provides huge suspense and also some hilarious results / effects for the readers. It allows us to feel or see the side of the story that before the characters do, but more importantly it builds the suspense for how the story will end.