Quadruple murder in Rupperswil: controversial search method was useless

Quadruple murder in Rupperswil: controversial search method was useless

The Rupperswil case is considered to be the first major digital investigation in Switzerland because the perpetrator was identified through an antenna search. But the thesis is wrong.

Andreas Maurer / CH Media

December 21, 2015 was like today Monday. Smoke rose over the village of Rupperswil in Aargau. There was a fire in a two-family house. The fire department found four bodies. During Christmas days, the news spread that a family had been murdered here. It was the beginning of one of the most important persecution campaigns in Switzerland. It lasted 146 days. Only then was the quadruple killer Thomas N.

With the Rupperswil case, a new search method became known: the antenna search. The Public Ministry and the Criminal Police evaluated the data from three cell phone masts near the crime scene. It contained the cell phone numbers of around 30,000 people whose devices had been connected to antennas in the hours around the crime. They can be calls, messages, or data connections from applications running in the background. The number of registered numbers is so great because all three antennas are on the railroad line and on the highway.

The search for antennas has been a success story ever since. Recognized experts spread the story that the aggressor was identified using this method. The researchers had no interest in denying this legend because the alleged success helped justify and fund future antenna searches. Because the method is very expensive. The federal government first charged the canton 816,000 francs for this, sparking a legal dispute.

The truth is that the antenna scan was useless in this case. Investigators found no evidence leading to the perpetrator. His cell phone number was in the data pile. The researchers only recognized the famous needle in the haystack when they identified the killer in another way and compared its number with the antenna data. They had another test, which they did not use in the process.

The state secret: why we still don’t know exactly

The investigation of this newspaper is based on sources from the police and the prosecution. Some cops are talkative because they are upset by the legend. Suggest that the computer programs solve the case or the office data specialists. It was the more than a hundred men and women on the streets of Rupperswil who did the classic police work.

For example, they closely observed the contents of each garbage can within a kilometer radius and rang the bell at each front door in the area to show residents a desired maneuver. No direct leads were received, but the profilers were able to collect indirect leads. They saw how people reacted. They also called Thomas N. It is not known if he was suspicious. Police say the method at least moved the investigation forward, as opposed to the search for the antenna.

What was the decisive approach in the end is a state secret and will remain so for the time being. Prosecutors want to prevent their actions from losing their surprise effect in future cases. For example, after a murder in Aarau in January 2019, the same method was used again, as it is called behind the scenes.

Therefore, no official confirmation is available to refute the myth. Given this, the two main investigators of the case make significant statements. Markus Gisin, chief of the Aargau criminal police, says: “It was not the only method that led us to the perpetrator. It was a mixture of different investigations. “And prosecutor Barbara Loppacher adds:” Searching the antenna alone is not usually enough to solve serious crimes. “