At the Omni Hotel downtown...he put his hands behind his back -- ready for the cuffs. Before the Austin Police Officer even got to him.
Just a few minutes prior, William Brady Cassidy, 22, assaulted a FOX 7 photographer for no reason at all.
It happened on Thursday afternoon in broad daylight. One of our photographers was standing on the Brazos Street sidewalk right next to the FOX 7 station, talking to a reporter in her car about a story. Someone came up, sucker punched him in the back of the head completely unprovoked.
Cassidy takes off down Brazos. Our photographer immediately dials 911.
Another FOX 7 employee gets her cell phone camera rolling and follows him around the corner of Brazos and Ninth.
That's when she sees him nearly attack a woman just walking down the sidewalk.
The woman screamed for help.
Eventually this guy walked over to the Omni Hotel where he asked to use someone's phone.
That's when APD showed up and arrested him.
During APD's investigation on Thursday they told us this was just one of several similar incidents in the downtown area that day.
"We have made an arrest in a couple of cases. The others are just assault complaints at this point," said Corporal Angel Polansky.
Corporal Polansky says our "hitter" may have been responsible for at least one other "punch and run."
Polansky says if something like this happens to you, get help and do it fast.
"Immediately find somebody to call 911. Anybody. Or call 911 yourself if you can," Polansky said. "Try to get a description of the individual if you can. And try not to delay your reporting."
She says when you're downtown, be aware of your surroundings, don't drink so much you lose control of your senses,and try to walk in groups or at least let someone know where you're going in case something happens on the way.
"Keep your heads out of your cell phones. That's a big one. People aren't paying attention to what's around them because they're looking at their cell phone," Polansky said. "Just always be aware. People just stop being attention...we're all guilty of it."
Cassidy is in the Travis County Jail with a $10,000 bond.
He's charged with Assault Causing Bodily Injury.