SAN SEBASTIÁN, Spain—The Basque militant group ETA said it has dissolved, bringing a formal end to half a century of assassinations and violence and leaving victims pressing for the investigation of hundreds of unsolved crimes.
ETA killed more than 800 people during its bloody and unsuccessful attempt to secure an independent Basque state stretching from northern Spain to southern France. The disbanding caps a decade that has seen the group slowly fade and cease to be a threat for Spaniards. ETA killed its last victim in 2010,...