Oktoberfest grounds closed after Munich blast, suspect dead.

Munich police closed the Oktoberfest fairgrounds Wednesday and evacuated nearby streets after authorities discovered a letter threatening the festival and following an early-morning explosion and house fire in northern Munich that left at least one person dead, officials said. The suspected perpetrator was found dead near Lerchenauer See with an explosive device, and investigators said preliminary findings indicate he killed himself.

Bavaria police identified the suspect as a 57-year-old German resident of Starnberg. Officers said the blast occurred before dawn at a residential building that had been deliberately set on fire. The suspect’s 81-year-old mother and his 21-year-old daughter, a German-Brazilian dual national, were injured and taken to hospital. Police said explosives teams were later called to the scene to defuse booby traps found inside the building.

Authorities said a letter found near the crime scene contained a nonspecific threat referencing explosives and Oktoberfest, prompting a full search of the festival grounds. More than 500 officers were deployed to the scene, police said, and explosions-detection teams, sniffer dogs and technical search equipment were...