Two Wells Fargo branches, a Chase Bank and a Compass Bank were robbed between 10:30 a.m. and 2:30 p.m., KTRK-TV, Houston, reported.
The first robbery took place at the Wells Fargo in the 10000 block of Beechnut, where a man passed a note to a teller and escaped with an undisclosed sum of cash, the report said.
Shortly thereafter two armed men robbed the Wells Fargo in the 2000 block of Taylor of an undisclosed sum.
At 11:45 a.m. a lone gunman fired a shot into the air after demanding and receiving cash from a teller at the Compass Bank in the 1200 block of West 43rd Street.
"I didn't panic. I just kind of went and hid," witness Bobbi Bilnoski told the TV station. "He told the teller to give up all the cash and she did."
Bilnoski said the suspect fired a single shot into the air as he was leaving the bank.
"He just waved the gun up. He made a shot," she said. "Didn't shoot at anyone in particular, but he made a shot."
A fourth robbery took place at 2:30 p.m. at the Chase Bank in the 5000 block of San Felipe, where a man said he had a gun but never displayed one. The man, who was caught on surveillance video passing a note to a teller, dropped some cash as he fled on foot, the report said.