The Houston Police Department officers say a crackdown in already underway against illegal "after-hours clubs" that serve alcohol after the legal closing time of 2 am.
Experience proves that such places attract public intoxication, fights, injury, guns and sometimes even death, they say.
On Sunday morning, a group of about 15 people were said to be milling around outside what may be an after-hours bar in the 12900 block of Nyack Drive, near the 45 Gulf Freeway at Scarsdale.
That's when someone drove up and started shooting into the crowd.
As the crowd dispersed, people started screaming while the shooter in the SUV drove off.
Four people were injured, two of them rushed to hospitals with severe gunshot wounds and both said to be in critical condition as of Sunday.
The other two were just grazed by bullets, according to police, and they'll be all right.
Police are working to find out why the shooter decided to spray the front of the business with gunshots.