How do you plan a defense for this?

[Bmyers]

https://www.foxnews.com/us/nashville-ex ... istmas-day

An explosion that shook downtown Nashville and injured at least three people Friday appears to have been "an intentional act," police said, as officials pointed to a suspicious vehicle that blew up at approximately 6:30 a.m. local time.

The FBI is investigating along with local officials and the Bureau of Alcohol, Tobacco, Firearms and Explosives, and the city of Nashville activated its Emergency Operations Center.

"This appears to have been an intentional act," Metro Nashville Police Department tweeted. "Law enforcement is closing downtown streets as investigation continues."

An audio warning was being broadcast before the explosion, according to videos posted online.

"If you can hear this message, evacuate now," the warning said.

[tom mac]

Still strange, warning given, but with a "shots fired" call to 911 prior, outside an ATT switch site for 911 calls
No big crater tho so low level explosion

[David]

How do you plan a defense? The only thing I can think of is upping situational awareness. But it's hard to see something suspicious about a vehicle parked on a street unless it's by itself or in an area were vehicles usually don't.

It will be very interesting to see how this unfolds and if motivations and suspects can be discovered.

[Ronin.45]

These are impossible to plan a defense against. You can't avoid walking past parked cars on the street.

[Bob]

You can't. However, there isn't a need to.