Florida man arrested after 'highly volatile' homemade explosives found at home during drug bust, deputies say

WINTER PARK, Fla. - What started as a search warrant for drugs at a home in Winter Park on Thursday ended up with the evacuation of several homes in the area after a homemade explosive was found, according to the Seminole County Sheriff's Office. 

Mark Severson, 40, was arrested and charged with possession of explosives and manufacture of explosives with intent to do bodily harm, according to deputies. Records show that Severson is a system engineer for an unnamed intelligence analyst.

The area where all this happened was in the middle of a quiet subdivision in Winter Park. Neighbors said this is not the first time this house has received attention from law enforcement. One man said he had noticed deputies near the home for the past few weeks. Another neighbor, Melanie Geiger, said she saw the same thing but didn’t think much of it.

"I always saw sheriffs go down that road, but I always thought they were just patrolling," said Geiger. "I had no idea."

Deputies executed a search warrant on Severson's home on Thursday for drugs, according to an affidavit. When they arrived, they found "numerous chemical powders" that were "consistent with pyrotechnic manufacturing and the manufacture of homemade explosives," deputies said. This discovery triggered a secondary search warrant to be obtained and executed, which was signed that day. 

Photo: Seminole County Sheriffs Office

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Deputies continued their search and tested the powders for explosive materials. They found a white crystalline powder which appeared to have been synthesized in the home, deputies said. It tested positive for triacetone triperoxide (TATP), a "highly volatile homemade explosive mixture that cannot be moved and must be disposed of in place due to the high likelihood of unintended detonation," the affidavit said. 

Officials said they found half-a-pound of TATP. 

Due to the powder's volatility, detectives evacuated five homes in the immediate vicinity for a short time on Thursday and conducted reverse 911 calls to neighboring homes in the Winter Park neighborhood on Alena Court. 

Neighbors were surprised at the news.

"It scared me," said Werner Theriauout, who lives on a street behind the house. 

"I just ran inside, because I was hearing helicopters and stuff and I just didn’t want to be involved in any of it," said Geiger.

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Officials decided not to remove the homemade explosives, but to dispose of them at the scene, a spokesperson for the sheriff's office said. So, the bomb squad blew it up right then and there.

"There was a big boom," said Theriauot. "Bunch of smoke going up in the air."

"I didn’t know what it was," Geiger added. "I just saw a bunch of smoke and everything," 

Severson was arrested and booked into the John E. Polk Correctional Facility.  The sheriff’s office requested that a judge not let Severson out on bond, arguing that he’s a risk to the public, but the bond has since been granted at $37,500 bond.

"I’m kind of nervous that he could come back and make more explosives," said Geiger.

On top of charges of possessing an explosive device with intent to cause harm, Severson also faces charges for possession of MDMA and marijuana, plus possession of meth with intent to distribute. 

Severson has been arrested in the past on charges of domestic battery, trespassing, and leaving the scene of a crash with property damages. As of Friday evening, Sanderson was still listed as an inmate at the Seminole County Jail.