Welcome to a special edition of the lead.

I'm Caitlin Collins in for Jake Tapper, and we begin this July 4th holiday with our

national lead and breaking news on the latest deadly mass shooting in America.

Authorities say at least six people have been killed, and at least another two dozen

have been taken to the hospital with serious injuries in the city of Highland Park, Illinois,

a suburb of about 25 miles north of Chicago.

It started when a 4th of July parade in the city's downtown area came to a halt after

multiple shots were fired.

Witnesses describe a chaotic and horrific scene with terrified adults and children running

for their lives, leaving camping chairs, strollers, and shoes behind.

An employee at a nearby gas station says about 20 parade goers ran and sheltered inside

as shots rang out, while others hid behind dumpsters and underneath cars.

The gunfire started just 14 minutes after the parade began as a band was playing.

Pictures in the massacre show multiple victims lying in the street with blood on them as

first responders arrived on the scene.

Here's how one witness described what they saw.

Well, a little bit after the band went through, we hear and probably heard 50 rounds in

total at least.

Everyone thought it was fireworks, everyone's like, oh, fireworks or the military people

had just gone through with the shotguns, and I was like, something's wrong.

I grabbed my dad and started running.

All of a sudden, everyone behind us started running.

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