Police must verify every lead after Aarau rave shooting

Deadly shots were fired at a rave in Aarau on Sunday morning, triggering a large-scale search operation. SRF reported that Aargau police had arrested a 43-year-old suspect, while the investigation continued.

Thomas Herzing, a violence prevention specialist with more than 30 years of experience in police, criminal police and security authorities, explained how such an operation works.

Protecting the public comes first

In the first phase, police must organise the large amount of information they receive and reduce the danger to the public as quickly as possible. Protecting people takes priority over pursuing the suspect, Herzing said.

Police must also secure medical care for the injured. Witness statements are particularly important when recorded as soon as possible. At the same time, criminal police begin forensic and investigative measures and try to establish what happened.

Evidence such as cartridge cases can indicate the calibre and type of weapon used. Witness accounts and video recordings are also important pieces of the investigation.

People who provide evidence to police should do so as early as possible without assessing it themselves, Herzing said. Drawing personal conclusions or sharing evidence publicly can make the investigation more difficult.

Witnesses can misremember details

Help from the public is very important, but human perception is prone to error. The longer ago an event occurred, the harder it can be to recall verified facts accurately. Information reported in the media can also influence people’s perception and their testimony.

Herzing recalled once describing a getaway car as a civilian witness. The car was green, he said, but he would have sworn that it was red. The example showed how unreliable perception can be.

Police may also seek information through social media. But attempts by people to attract attention on platforms such as TikTok can be counterproductive if they reveal information important to the investigation or fuel further speculation.

Information must be checked

“Information is not yet insight,” Herzing said. Every lead must first be checked before it can become a reliable line of investigation. Because police must follow up on every tip, unverified information can delay their work.

A large-scale search does not necessarily lead to an arrest within a few hours. Speed is important, but investigators must still assess the reliability of different findings and bring them together. A wrong conclusion can have serious consequences for the course of an investigation.

While 24 hours may feel like a long time to the public, it is a very short period for complex investigative work, Herzing said.