The Discordance-and-Origin Principle in Murder Investigations

The Discordance-and-Origin Principle in Murder Investigations is Amaia Salazar’s approach to reading a crime scene against its apparent pattern: the detail that does not fit may reveal the hidden origin of the crime, while tracing that origin can disclose its eventual shape. In the linked murders she investigates, the principle turns an unexplained missing arm and a repeated written mark from anomalies into a path toward the person manipulating the killers.

The First Discordance

At first, the amputation in the Lucía Aguirre case could be treated as incidental. Amaia considered ordinary explanations, including that the killer had removed a hand to take a ring or hinder identification, though neither made much sense in the victim’s own home. That uncertainty mattered: the cut was not yet proof of a shared offender, but it was a detail that resisted the straightforward account of the murder.

A second irregularity was the word Tarttalo, scratched into a cell wall by Ramón Quiralte with the handle of his toothbrush. Quiralte had confessed to killing his wife but denied responsibility for the amputation. The written mark, like the missing arm, suggested something beyond the violence the confession appeared to explain.

From Similarity to a Pattern

The examination of Lucía’s remains brought the case into comparison with the killing of Johana Márquez. Dr. San Martín found that the postmortem cut resembled the one in Johana’s case, but stressed the limits of the evidence: photographs could show similarity in technique, not establish that the same tool or person was responsible. Physical samples would be needed for a more conclusive comparison.

Amaia presented the cases to the judge as a possible connection. Both women had suffered the same unusual removal, and the men who confessed to killing them later left similar messages. A further murder in Logroño added to the pattern: its killer died by suicide in his cell after leaving the same word, with the same unusual double-t spelling. Yet the apparent commonality did not erase the differences. The men fit familiar patterns of abuse, while the postmortem removal and the absent limb stood apart from those patterns. The principle requires keeping both facts in view: repetition can connect cases, but the element that does not belong may point beyond the apparent perpetrator.

The investigation also widened beyond the initial cases. Amaia found two more women born in the valley who had been killed by partners, one in Bilbao and one in Burgos. Their deaths supported a broader search for connections, but the available records did not establish whether either woman had also suffered an amputation. The principle therefore guides inquiry without turning every resemblance into proof.

The Exception That Exposed the Source

Jasón Medina presented a particularly important mismatch. He did not fit the aggressive, violence-prone profile Amaia saw in the other men, and Johana was the only victim in the comparison who had been living in the valley when she died. Medina confessed to killing her but appeared genuinely unable to explain the missing arm. He had left the scene and returned later; in his absence, someone else had taken it. His account, together with the surrounding circumstances, made it possible to distinguish his crime from the additional act that linked it to the wider series.

Amaia reasoned that the person who took the trophy must have been present at the right moment. Because Medina had acted impulsively, the appearance of that person was not readily explained by a prearranged plan; Amaia concluded that he had been followed. In the novel’s later account, the deeper discordance lies in the orchestrator’s own departure from his established pattern: his fixation on Johana led him to act from obsession and made him vulnerable to detection. The investigator’s attention to what does not fit thus shifts the question from how the murders resemble one another to what exception could reveal the hand behind them.

Amaia’s Formulation

When Dr. Berasategui asked whether Amaia had understood the matter, she answered first with the discordance and the beginning, then reversed the order and repeated the idea as the beginning and the discordance. She explained that in a murder investigation the discordance provides the key, while the beginning provides the origin, and that the origin contains the basis of its end.

The principle is both a practical discipline and a way of organizing the investigation’s revelations. Similar cuts and repeated messages invite comparison, but neither should be mistaken for a complete explanation. The crucial clue emerges from the friction between the apparent pattern and the case’s exceptions; tracing that exception back to its source exposes how the crimes were connected and why the pattern eventually broke.