William Krar and Judith Bruey appeared a perfectly normal couple. Certainly Teresa Staples thought so. She remembered a polite, sociable couple who always paid their rent on time for the three garages they rented from her.
~~~

She was right. Among a terrifying arsenal of guns, bullets and bombs, the FBI found a chemical cyanide bomb. Used in a shopping mall, a stadium or a subway, it could have killed thousands. 'I was terrified. I live here with my children and they had that terrible stuff in there,' Staples said.
~~~

But FBI agents uncovered the cache of weapons hidden behind them. More weapons were found at Krar and Bruey's secluded home in the pine woods that surround Tyler. Eventually the haul totalled 500,000 rounds of ammunition, more than 60 pipe bombs, other remote-controlled bombs disguised as brief cases, and dozens of machineguns, silencers, pistols, mines and explosives.

And, inside an ammunition cannister, was the sodium cyanide, next to quantities of acid that would act as a trigger for the device, reacting with the cyanide to release a cloud of lethal gas.

(CNN)Stephen Paddock, who sent bullets and terror down on thousands attending a Jason Aldean concert in Las Vegas, had an arsenal in his 32nd-floor hotel room and at his home 80 miles away, officials said.

Police recovered 23 guns from his Las Vegas hotel room and another 19 guns from Paddock's home in Mesquite, Nevada, Clark County Assistant Sheriff Todd Fasulo said.

Authorities said Paddock killed 59 people and injured another 527 early Monday in the deadliest mass shooting in modern US history.

But what they couldn't explain is why the man who had never faced any notable criminal charges did it. There was no known motive late Monday.