Russia was left shaken after a deadly stabbing inside a Moscow school sparked a murder probe and extremism fears. A 10-year-old student was killed, while a security guard was critically injured during the attack that unfolded in broad daylight. A teenage suspect was swiftly detained, as investigators began examining disturbing symbols, digital footprints, and possible ideological motivations. Authorities are now racing to piece together how a quiet student allegedly moved toward violence, and whether radical influences played a role.