Investigators need help finding a man who robbed a southwest Houston bank.

FBI officials said the man walked into the Prosperity Bank in the 8300 block of the Southwest Freeway near Gessner about 2:45 p.m. Monday.

The man handed the teller a note demanding cash, investigators said. He also lifted his jacket to reveal a gun in his waistband, officials said.

The teller handed over an undisclosed amount of cash and the man fled on foot, detectives said.

The robber was described as white, 30 to 40 years old, 5 feet 7 inches to 5 feet 8 inches tall with an average build and clean-shaven. He was last seen wearing a dark-colored jacket, blue jeans and a black ski cap with "Chicago Bulls" written in red lettering.

Anyone with information is asked to call Crime Stoppers at 713-222-TIPS.