Here in Finland there was interesting example where someone was selling hitman services over tor-network. They caught him because he left a plastic bag in the crime scene, the plastic bag had a sticker, from that they could tell that it had been used to weight a banana and could also pin down the place and a time. They then used the surveillance footage in store to identify the person.

It’s not easy to compare such rates between countries. Especially in terms of finding the correct killer vs someone to blame.

Also, “this study did not include cases of missing persons where no body was found. In all four countries, such cases are usually labelled as a disappeared person, even if the police strongly suspect a homicide. Following other studies (Sturup et al., 2015), because of the unknown nature of these cases (including potential suicides or voluntary disappearances), these cases have not been included in the study. This may have resulted in a general under-count of the total number of homicides, including an under-count of unsolved homicides.”