House explosion in northern Virginia was caused by man igniting gasoline, authorities say

ARLINGTON, Va. -- A man who died in a house explosion six months ago outside the nation's capital deliberately detonated gasoline canisters in his basement that caused the blast, authorities said Friday.

Arlington County police in Virginia went to the home of 56-year-old James Yoo on Dec. 4 because he was firing a flare gun from the back of his duplex into a nearby school and park, police said Friday at a news conference announcing the cause of the explosion.

Police tried unsuccessfully to make contact with Yoo. They got a search warrant and used an armored vehicle to knock through his front door. Officers then heard gunshots, and a few minutes later the entire house exploded.

"Unfortunately, we're not going to know" a specific motive, Police Chief Andy Penn said Friday, though the investigation turned up evidence of paranoia and mental health problems.

The case has no ties to terrorism, and Yoo acted alone, FBI counterterrorism agent Sanjay Virmani said.

Authorities showed dramatic video of the explosion at Friday's news conference, taken from police dash cams and body-worn cameras of officers. It also showed body cam video of children in a nearby park frightened by the flare gun shots and efforts by officers to talk to Yoo and get him to come out of his house.

None of the first responders suffered major injuries, though Penn said several officers ended up seeking medical care in the days afterward.

Authorities had previously disclosed that Yoo had exhibited erratic behavior and frequently contacted the FBI alleging that he was a victim of schemes and frauds. Court records show he also filed federal lawsuits that were dismissed as frivolous. Some of the lawsuits, filed from 2018 to 2022, were described by judges as "convoluted" or "confused." One lawsuit alleged he had been committed against his will.

Investigators concluded that Yoo intended to start the fire that caused the explosion, an agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives said Friday. Investigators found gasoline canisters with 35 gallons of capacity stored in his basement.

The agent said they could not conclude exactly how he ignited the fire and explosion, and said it could have been caused by gunshots igniting gasoline vapors or simply by a match or lighter.

Police used pepper spray and tear gas to try to force Yoo out, but authorities had said previously, and again at Friday's press conference, that those chemicals are not flammable. They had also turned off the natural gas connection to the home in the early phase of the standoff.