 Item Number – SCP-4087 Object Class – Euclid Special Containment Procedures Foundation assets embedded in European and American law enforcement agencies are to monitor ongoing homicide investigations for markers consistent with the use of an SCP-4087 instance. When these markers are found and no murder weapon exists, a replica of similar make and design is to be provided. In the unlikely event that an additional instance of SCP-4087 is recovered, it is to be immersed in a cubic meter of concrete and transported to a deep geological repository for indefinite storage. Description – SCP-4087 is a set of antique spring-driven push-button knives. Each blade is 9.2 cm in length and composed of stainless steel. They were produced by Gavrilo Maniago, an Italian knife maker, as part of a private commission. He only completed six prior to his murder in 1914. SCP-4087 was first identified in 1973, after a mathematical model created by the Foundation's Department of Analytics linked them to over 100 homicides across 50 years. In each case, law enforcement identified one of the six knives as the murder weapon. Each knife was repeatedly lost, returned, or auctioned off. As of 1975, all six knives have been recovered and accounted for. Since then, over 200 additional homicides have identified an identical knife as the murder weapon. An investigation into these homicides has determined that, despite all evidence to the contrary, no actual murder weapon exists. After a thorough forensic examination of all six knives, researchers have made the following observations. They exhibit no observable anomalous properties. They lack any sign of significant wear or use.