The gunman killed three men and wounded Austin and one other person before he was killed by police.
Cincinnati Mayor John Cranley says the first responders and the police officers who confronted and killed the gunman showed true heroism and bravery. He was armed with a 9mm handgun and hundreds of rounds of ammunition.
"A very horrific situation", Isaac said at the scene.
Authorities searched an apartment about 15 miles west of downtown in North Bend, where they believe Perez lived.
The chief said he did not know if the suspect, who had lived in the Cincinnati area since 2015, had any history of mental illness.
Streets and sidewalks around Fountain Square were closed.
(Albert Cesare/The Cincinnati Enquirer via AP) A woman is comforted by authorities stationed outside the University of Cincinnati Medical Center's Emergency room following a shooting in downtown Cincinnati that left at least four dead, including the gunman, and several injured on September 6, 2018. It is home to retail stores, business offices, hotels and eateries. He had been working as financial consultant in the Fifth Third bank for the last three- years.
Witnesses described a chaotic scene, with people running away in fear and confusion while hearing gunshots.
Police had not publicly identified the two others killed. She says she was relieved to survive, "to see my kids, to see another day". Pruthviraj, who went to the United States six years ago for his postgraduation, was working as a financial consultant in a bank in Cincinnati.
Another employee, Michele Parks said she was about to go into the bank when Cook stopped her.
Jessica Hanson said her co-worker was in shock and that's when people in her office found what had happened. 5/3rd Building on Walnut, downtown Cincinnati. "We're a bit rattled", said a Fifth Third Bank manager.
Dozens of law enforcement officers and medics swarmed the scene.
Ohio Gov. John Kasich called the shooting "senseless" and commended officials' swift response.
Eric Kearney, president of the Greater Cincinnati and Northern Kentucky African American Chamber of Commerce, was in a board meeting across the street from the bank. Police also hope to get clues to the gunman's movements from surveillance video from the building and outside near the square.
The Cincinnati Reds announced that the team planned to have a moment of silence "in honor of the victims" before the national anthem at Thursday night's game against the San Diego Padres.