“A growing sense of alarm spread across Texas’ capital city Monday as the authorities confirmed that a new makeshift bomb that injured two people in southwest Austin on Sunday appeared connected to three earlier explosions, but suggested a “higher level of sophistication” with the use of a tripwire triggering device.

““We are clearly dealing with what we expect to be a serial bomber at this point,” Brian Manley, Austin’s interim police chief, told reporters as parts of Travis Country, where the latest bombing occurred, were placed on lockdown through midafternoon.

“Residents there had been asked to remain indoors through the early part of the day and look out for suspicious packages, like backpacks or boxes — meaning nearly every parcel in this city of 947,000 was suddenly an object of potential suspicion.”

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