Detailed Explanation
Jonathan Fraser murdered Elena Alves—the answer the show teases for six episodes but delivers with devastating impact. Jonathan had been having an affair with Elena, lying to both her and Grace. When Elena threatened to tell Grace about the affair and Jonathan's other lies, he beat her to death with a hammer in her art studio. The show makes viewers question the obvious answer, introducing red herrings and making us doubt what we're seeing. But the truth was in front of us the whole time: the charming surgeon was a monster.