By Ray Sanchez, CNN

(CNN) -- The locked closet in Randall Drake's home in Dunedin, Florida, did not yield any child pornography that detectives suspected was hidden there, Pinellas County Sheriff Bob Gualtieri said.

Instead, they came upon an arsenal that included homemade explosive devices, 10 rifles, eight handguns, two shotguns, more than 2,300 rounds of ammunition, tactical jackets, a homemade silencer, assorted knives, a crossbow and gunpowder, Gualtieri told reporters Thursday.

There were aerial photographs of an elementary and middle school as well as a water treatment plant in Hillsborough County, according to the sheriff. There also were books and notes on making explosives, and a handwritten note that ended, "I shall have my bloody revenge, and then the WORLD WILL BURN BURN."

Drake, 24, was arrested and charged Wednesday with two counts of unlawfully making, possessing or attempting to make a destructive device. The child pornography he was suspected of distributing has not been found, said Gualtieri, without elaborating on that investigation. Drake's computers were seized.

On Thursday evening, Drake was released on $20,000 but was held under Florida's Baker Act -- which allows mental health facilities to hold a person for up to 72 hours for evaluation, according to county officials.

"If they release him," Gualtieri said, "there's nothing I can do about it."

Drake's attorney, Summer Goldman, declined to comment Friday.

No criminal history

Before the child porn investigation, the suspect was not known to authorities, Gualtieri said. He had no criminal history.

Drake was home-schooled after the third grade and lived with his parents in Dunedin, a city about 25 miles northwest of Tampa, the sheriff said. He was a former Police Explorer, which introduces young people to careers in law enforcement.

Drake's last known job was at Tampa's Florida Firesarms Academy, a shooting range that offers firearms training, Gualtieri said. He lost that job in 2015, the sheriff said.

"He came into work armed with a gun strapped to his thigh, wearing a flak jacket, and they didn't want him working there anymore after he did that," Gualtieri said.

'It's very troubling'

Drake has not made any statements to investigators, according to the sheriff. His parents told detectives they knew he had guns but not as many as were found in his room closet.

"What's driving this? ... We don't know," Gualtieri said. "He won't talk to us."

Some of the weapons found were improvised. The silencer was fashioned from an oil can, the sheriff said. Two homemade explosive devices were constructed of metal cylindrical cigar tubes with gunpowder and wicks. A third device was made from a plastic tube filled with gunpowder, wrapped in tape, with a fuse attached.

"You've got a kid who is 24 years old," Gualtieri said.

"He's got three bombs, a whole cadre of weapons, 2,300 rounds of ammunition. He's got a note that says everybody's going to burn and you have him with maps and aerial overviews of an elementary school in Hillsborough County, a middle school in Hillsborough County and a water treatment plant. ... It's very troubling."

Drake's girlfriend told investigators that he's "a nice guy and not violent," according to the sheriff.

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