"Upon searching the area, the deputy found a metal pineapple-style grenade with a paperclip in place to hold the lever and keep it from exploding," Gant said.
The grenade didn't contain explosive powder, but Langer had about a dozen homemade blasting caps and numerous chemicals, including nitric acid and urea, which were used in the 1993 World Trade Center bombing, Volusia County Sheriff Mike Chitwood said Monday.
"That domestic violence call probably saved us from making national, international news," Chitwood said. "He has all of the components in there to make a weapon of mass destruction."
Langer also had manuals about how to create booby traps, Chitwood said.
"He had a lunchbox -- a SpongeBob SquarePants lunchbox -- that was all set to go. All it needed was a battery and gun powder," Chitwood said. "He told investigators his intention was to hurt first responders. He wanted to take revenge against the system."
Investigators said they discovered a small canister buried in the backyard covered by a toy. They said the device is a booby trap, describing it as a miniature pipe bomb without explosive powder.
Deputies said they also discovered a hollowed book and an estimated 200 containers in the home, many of which contained unknown powders, acids and other materials.
Deputies said at least 79 of the containers were moved into a containment area, where it was determined that many of them were filled with bodily fluids.
Chitwood said Langer's room was in a deplorable condition and contained bottles of urine, which he said can be used to make bombs.
"If I was a roach, I wouldn't live in that room," Chitwood said. "That's how despicable and dirty and feces- and urine-filled that room is. Yet the rest of the house is in pretty good shape."
Deputies said Langer had been committed for a psychological evaluation under the Baker Act four times. They said paramedics administered Narcan on him at the home two weeks ago after he overdosed on heroin.
Langer told detectives that he espoused anti-government views and sought to maim first responders, Chitwood said.
"He didn't take the overt step to put all these things together to create the bomb," Chitwood said. "He has everything laid out, ready to go. He's tested the mechanism, he just hasn’t mixed it."
Investigators said some neighboring homes were evacuated, but residents were allowed to return to their homes Sunday evening.
"He could have blew up the block," Chitwood said. "We could have had a major, major incident here."
Langer was booked into the Volusia County Jail on charges of making/possessing a destructive device. He's being jailed without bail and could face more charges, Gant said.