A gunman killed one and injured five, police said, in a shooting Friday at the Orlando offices of an engineering firm where the suspect was let go more than two years ago.

The shooting set off an intense manhunt Friday afternoon until the alleged gunman, Jason Rodriguez, 40, was arrested without incident at his mother's Florida apartment building, police said.

He has been charged with first-degree murder.

Asked by a reporter outside the police station why he did it, Rodriguez said: "Because they left me to rot," The Associated Press reported.

The five wounded were taken to the emergency department at Orlando Regional Medical Center, Orlando Police Chief Val Demings said. Another person suffered chest pains related to the incident.

SLIDESHOW: Orlando Office Shooting

"This is a tragedy no doubt about it, especially on the heels of the tragedy in Fort Hood that is on our minds," Demings said. "I'm just glad we don't have any more fatalities or any more injuries than we currently have."

Demings said the weapon used was a handgun.

The shooting started at Reynolds, Smith & Hills, a transportation engineering consulting firm where Rodriguez was laid off in 2007. The firm is located in the Gateway office building in downtown Orlando, and the shooting occurred on the 4th, 8th and 12th floors of the building, MyFoxOrlando.com reported.

Renato Gonzalez, a manager in the firm's DeLand, Fla., office, told Fox News that Rodriguez had done architectural work for the company and his layoff was part of cutbacks at the firm.

"I know that we was not very happy with the layoff," said Gonzalez.

Gonzalez recalled that Rodriguez made disgruntled comments when he left the firm, though nothing that indicated he would resort violence.

Company spokesman Mike Bernos said Rodriguez was fired after working at the company for a year.

"His performance wasn't up to our standards, so we terminated him," Bernos said.

There had been no contact between the company and Rodriguez since then.

Rodriguez started struggling financially after being fired from Reynolds, Smith & Hills.

He recently told a bankruptcy judge he was making under $30,000 a year at a Subway sandwich shop and owed nearly $90,000.

Les Winograd, a spokesman for Subway Restaurants, said Rodriguez had worked for one of the company's sandwich shops in the Orlando area until six weeks ago. He would not say whether Rodriguez had left or was fired.

Rodriguez's former mother-in-law told Fox News over the phone that Rodriguez was on medication that affected his mind. She said he acted paranoid, thinking people were out to get him.

"He would imagine things sometimes," his former mother-in-law said. "From what I understand they had him in a mental institution six months ago."

Her daughter had a son with Rodriguez. The former mother-in-law said her daughter was scared of Rodriguez sometimes.

Gerry Gilgo, who works on the floor where the shooting occurred, told The Associated Press she was meeting a co-worker at the elevators for lunch.

"She yelled, 'There are gunshots! There are gunshots! Get back in your office,"' Gilgo said.

Will Halpern, an attorney works on the building's 17th floor, was among the last group to be evacuated. He said the lobby was filled with about 20 officers in SWAT gear, carrying assault weapons, ready to search.

During the manhunt for Rodriguez, Interstate 4 was closed in both directions through downtown and nearby schools were put on lock down.

The FBI is assisting police in their investigation. Police said they do not know the motive behind the shootings.

The Associated Press contributed to this report.

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