She was rejoicing with him.

He pulled himself together, and told her what little he knew; not much more than the bare facts contained in the papers.

It was now known by the Marchesa's confession that the murder took place inside the Colle Alto gardens.

Everyone, including the police, had believed that the murder took place in the road, and that the assassin took advantage of the accident of the garden door being unlocked to drag the body into the garden, and hide it there.
But the Marchesa stated that she stabbed her husband in the garden suddenly without premeditation, but with intent to kill him, because of his determination to marry their seventeen year old daughter to a friend of his, a _roue_, the old Duke of Castelfranco, who drank himself to death soon afterwards.
The Marchesa stated that she dragged the body behind a shrub, walked back through the garden to the house with the front of her gown covered with blood without being noticed, found no attendant in the cloak room, wrapped herself in a long cloak not belonging to her, told her servants that the Marchese would follow later, and drove home, partially burned her gown and the cloak as if by accident, and then awaited events.

The first news she received of her husband's death next morning was accompanied by the amazing information that Michael had confessed to the murder.
The Marchesa in her tardy confession stated that she believed Michael, who had always shown her great sympathy, must have actually witnessed the crime, and out of a chivalrous impulse towards her, had immediately taken the guilt of it upon himself.
"That accounts for his extraordinary silence," said Wentworth, "not only to others, but to myself.