CINCINNATI – A gunman carrying hundreds of ammunition opened fire in a downtown building on Thursday, killing three people and injuring at least two others before he was fatally shot by the cops.

Police Chief Eliot Isaac said three or four policemen exchanged fire with the shooter, identified as Omar Santa Perez. Perez, 29, was armed with a legally purchased 9mm semi-automatic pistol, said Isaac.

No reason for the carnage had been immediately determined. The mayor of Cincinnati, John Cranley, said the shooter seemed to be targeting random people during the "horrible" attack.

"There is something deeply sick at work here, and as a country, we have to work on it," said Cranley.

Hamilton County Attorney Joe Deters told WLWT-TV that the police's quick response had probably prevented many victims. He said the officers immediately indicted gunfire from Fifth Third Bancorp's 30-storey headquarters along the Cincinnati Fountain Square.

He says that an investigator told him that the suspect had enough ammunition to cause "a bloodbath beyond the imagination".

According to the records available online, Perez was a resident of North Bend, Ohio, who previously lived in South Carolina and Florida. Police searched his apartment in North Bend on Thursday afternoon, looking for clues about the attack or his mobile.

Perez is an American citizen born in San Juan, Puerto Rico, family members said Thursday. Yudy Martinez Perez collapsed crying in the kitchen at her park in Forest Park, Ohio on Thursday afternoon when she learned that her nephew was the gunman.

"Oh, no, no, no, no," said the woman as she slumped against the wall and spoke to Perez's sister.

Isaac stated that the rampage took place on the loading dock and then in the fifth center lobby in the heart of the city center. A phalanx of police and ambulances rushed to the scene at the height of the morning.

Councilman P.G. Sittenfeld was the first in charge of the city to reveal that the aggression had resulted in death.

"A terrible shooting incident in the heart of our city this morning," Councilman Sittenfeld. "Multiple blows, and tragically there are deaths, details still coming in. Pray for our city."

Pruthvi Raj Kandepi, 25, Richard Newcomer, 64, and Luis Felipe Calderón, 48, Hamilton County Coroner Lakshmi Sammarco were killed.

One witness said he heard up to 15 shots. Leonard Cain was entering the bank when someone alerted him of the shooting. He said that a woman was also going into the bank and that people were trying to get her attention, but she had headphones.

"She went into the door and shot him," Cain said.

Michael Richardson, who works in the building, was right outside the main doors, smoking a cigarette when he heard gunshots. He said he saw a man shooting with a gun in the lobby of the bank.

"I looked behind me and saw the guy – he fired and then he fired again," Richardson said. "After that, I started running."

Police said two people were injured. The University of Cincinnati Medical Center said that two victims had died in the hospital and that one survivor was in critical condition and another was in serious condition.

"We are preparing for such situations and hope that they will never happen," said Amanda Nageleisen, spokesperson for UC Health. "Our thoughts and prayers are with the victims, their families and all those involved."

Radio traffic indicated that other victims have been transported to the Good Samaritan Hospital.

Governor John Kasich and Ohio Senators Rob Portman and Sherrod Brown said they were monitoring the situation.

"There was a senseless act of gun violence on the streets of Cincinnati this morning," Kasich said. "I spoke with the mayor and informed him that the state would provide all the necessary resources to the local police.

The building is located on Fountain Square, an entertainment and dining center of the city.

Fifth Third Bank is one of Cincinnati's dominant financial institutions with 121 local agencies. The shooting took place at the head office, a skyscraper on the main square in downtown Cincinnati.

"What a tragic way to start this day," Sittenfeld said. "The scourge of gun violence is just losing."

Steve Conner lives on the first floor of the building where the Perez lived. Conner said that Santa Perez often walked, "looking (angry) everyone … he looked crazy on his face."

Connor said Perez often ignored Conner's attempts at salvation.

Perez's aunt stated that her nephew was in various jobs and was currently working, although his aunt and family did not know where.

"He was very quiet," said Martinez, who speaks little English. "I do not know why, I do not know why."

Perez's criminal record is a handful of petty offenses: enter or refuse to leave the premises in Greenville, South Carolina; possession of marijuana in Palm Beach, Florida; traffic violations in Lake Worth, Florida; traffic violations in Deerfield Beach, Florida; Messy driving in Coconut Creek, Florida. He also committed a traffic violation in Cincinnati in 2015 for driving with an expired license plate.

Bacon reported for USA TODAY from McLean, Virginia. Contributors: Bob Strickley, Sharon Coolidge, Anne Saker, Kevin Grasha and Sarah Brookbank, Cincinnati Enquirer

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