Investigators are focusing on social media posts made by the suspect, including a 30-minute audio recording, which they say support anti-natalist views.

One person was found dead, and the FBI said it was sending investigators, including bomb technicians, to the scene.

Bruce Springsteen’s criticisms of Donald Trump last week appear to have triggered the president even further, as he is now calling for an investigation of the superstar singer’s endorsement of Kamala...