Zephen Xaver, 21, burst into a SunTrust bank branch in Sebring on 23 January, according to an affidavit released last month.
He then made the five women inside the bank lie face down on the floor, and he fatally shot each one, the affidavit states.
A sixth person, a bank employee, had been in a break room and escaped through a back door when he heard the shots around 12.30pm, police said at the time.
Xaver was arrested at the bank after the shooting and was charged with five counts of first-degree premeditated murder.
In an initial court appearance just after his arrest, he was ordered to be held without bond at the Highlands County Jail in Sebring, a city of about 10,000 people about 80 miles south of Orlando.
Peter Mills, an assistant public defender assigned to Xaver’s case, declined to comment on the indictment when contacted on Friday.
At a televised news conference on Friday, the state attorney for the 10th Judicial Circuit said that a grand jury had returned the decision to indict Xaver, who will be formally arraigned on 25 February on the five charges. He added that he would be seeking the death penalty.
“As this case moves forward, I will seek the ultimate punishment,” said the state attorney, Brian Haas.
He added that seeking the death penalty was appropriate considering the “horror” of the shooting. “It was the obvious conclusion to reach,” he said.
While he was still inside the bank after the shooting, Xaver, who was wearing a T-shirt that bore the image of four scythe-wielding grim reapers on horseback and a bulletproof vest, called police.
“I have shot five people,” he said, according to a police statement released on 23 January.
The Sebring Police Department and the Highlands County Sheriff’s Office found the gunman barricaded inside the branch.
After a standoff with police negotiators, an armoured police vehicle rammed into the bank doors, and SWAT team members persuaded him to surrender, according to video footage and a statement released by authorities.
The names of three of the five victims were released at news conferences last month.
Police identified a customer, Cynthia Lee Watson, 65, and one of the four employees, Marisol Lopez, 55. A third victim, Ana Piñon-Williams, 37, who was also an employee, was identified by a family member separately.
Relatives of the other two employees initially declined to allow their names to be publicly released, police said. But their names were later published in local media outlets and released in the indictment on Friday as Debra Cook, 54, and Jessica Montague, 31, both tellers.
Last month, Chief Karl Hoglund of the Sebring police said police were still investigating the motive for what he called “coldblooded murder”.
Commander Curtis Hart said on Friday that Xaver purchased the handgun and the ammunition used in the attack about a week before the shooting, but he declined to say where.
When asked for more details about the motive and where he had purchased the gun, Mr Haas said it was too soon to reveal more.
“At this point, we are not able to talk about anything that he may have said,” Mr Haas said.
New York Times