The burly 56-year-old held a Florida school board at gunpoint Tuesday, saying he was prepared to die. He fired at board members, missing them by inches, then killed himself after exchanging gunfire with a security guard.
Duke's wife said Wednesday he was an excellent marksman and probably missed the five board members - sitting steps away - on purpose. One board member even crept up from behind and hit Duke with her purse - but he only called her a name and didn't shoot.
"He didn't want anyone to get hurt but himself," Rebecca Duke said of the man she loved. She called him a
"The economy and the world just got the better of him," she said.
In the moments prior to the shooting, Duke spray painted a circle and a large, red V inside of it on the meeting room wall and muttered about rising taxes and how his wife was fired from the school district. The school superintendent begged Duke not to shoot, but he did.
No one but Duke was injured; a school security guard, Mike Jones, fired several shots and hit Duke three times in the back. Jones wounded Duke at least three times, in his back and midsection, reports CBS News correspondent Mark Strassmann.
In the end, Duke took his own life by shooting himself in the head.
Police said the attack wasn't some spur of the moment idea. At his mobile home in the woods, they found Dec. 14 circled on a calendar. And police said he had at least 25 more rounds of ammunition in his pocket.
Police say Duke also conducted some "intelligence-gathering" at the site after seeing ROTC cadets carrying fake weapons outside.
"What he did was begin questioning them as far as whether their weapons were real, whether they were loaded. What we believe, at that point, he was conducting his own intelligence gathering mission prior to going inside the school board," Panama City Deputy Police Chief Robert Colbert told CBS' "The Early Show".
The entire shooting was captured by local television stations, and the video was posted on the Internet and broadcast on TV throughout the day. His Facebook page, which was public until late Wednesday afternoon, revealed a man who was fascinated with the movie "V for Vendetta" - which depicts the same symbol that Duke spray painted onto the wall just before he took out his gun.
"We do know that he was active on one of the social sites and that he had quite a few postings that were anti-government and … he had began to get quite a gathering, as far as people chatting with him through the social site," Colbert said.
As board members gave television interviews about the harrowing experience, a sad and troubling portrait of Duke emerged.
Born in Ocala, Fla., Duke graduated from high school in Tampa. Little is known about his early adult years - family members claimed he was in the Air Force for eight years, but that could not be confirmed.
In the mid-1990s, Duke had drifted to the Florida Panhandle - not the spring break-filled sugar sand beaches, but the remote and wooded inland.
The '90s were a blur of court hearings and personal conflicts.
He divorced a woman named Anita in 1995 and at some point, had a daughter. He was sued by a property management company in 1999. In 2000, he was convicted for waiting in the woods for his ex-wife with a rifle, wearing a mask and a bulletproof vest. She confronted him and then tried to leave in a vehicle, and Duke shot the tires. His second wife, Rebecca, said the incident was a misunderstanding and that he went to his ex-wife's house because the ex-wife "wouldn't leave them alone."
Duke's attorney on the case, Ben Bollinger, remembered Duke as especially paranoid about the new millennium.
"He was one of these Y2k people," he said, referring to a computer bug that some people thought was going to cause massive problems and economic chaos Jan. 1, 2000. "He was one of those believers that the world was going to turn for worst and he was stockpiling weapons, assault weapons."
Bollinger said Duke took a plea agreement: Five years in prison followed by 10 years probation. A judge relieved him of the probation obligations in January after Duke said he was unemployed and his wife might soon be. He said he was looking to move to a better place to find a job, according to court documents posted on the Smoking Gun website.
He also sought psychiatric help and took his medications as ordered and completed his probation, his lawyer said.
"He was competent but he was one of those people had a mood disorder where they could be depressed one day and all excited another day. I just remember the doctor saying he had a personality disorder," Bollinger recalled.
While in prison, Duke filed for bankruptcy.
He was released in January 2004. About a year later, he sued the Social Security Administration, which had denied his application for disability benefits and health insurance.
"He couldn't work. He just mentally couldn't make the connection for eight hours a day," said David Evans, the attorney who represented Duke.
Evans said Duke had been diagnosed by several doctors as bipolar, but didn't have enough money to buy the needed medication. "He was clearly in need of help," Evans said.
They filed at least five appeals to the denials.
"The judges adjudicating the claims didn't feel the claim was significant enough," Evans said. "All he was asking for was $500 or $600 a month and medical insurance."
Duke withdrew the suit in 2006.
He and Rebecca had married in 1999, just before his prison sentence. She said Wednesday that Duke faithfully took his medication for his bipolar disorder, but that he was under a lot of stress - she had been fired from the school district and her final unemployment check was due this week.
Tommye Lou Richardson, the executive director of human resources for the Bay District, said Rebecca Duke was hired in September 2009 as a primary school teacher for students with special needs. She was given a 97-day probationary period, and was terminated.
"She was not performing appropriately, we thought, the principal thought, and so she was let go," Richardson said.
She wasn't able to go into any further detail.
Richardson said Rebecca Duke had "indicated that she felt like there was a violation of her employment rights," though she never filed a lawsuit.
About a week ago, Clay Duke joined Facebook. Over the past several days, he added photo stills from the movie and graphic novel "V for Vendetta," a nihilistic account of a masked man who fights against a totalitarian government. The movie's predominant symbol - a red "V" inside of a circle - was posted several times on Duke's page.
He also quoted the final passage from Percy Shelley's "Masque of Anarchy": "Rise like lions after slumber/In unvanquishable number/Shake your chains to earth, like dew/Which in sleep had fall'n on you/Ye are many-they are few."
Duke had no Facebook friends - although by Wednesday afternoon, thousands of people responded to his earlier postings, many of them critical of Tuesday's shooting. Others were more sympathetic, saying that Duke was driven to madness because of the difficult economy.
Duke had written something of a suicide note in his "About Me" section:
"My testament: Some people (the government sponsored media) will say I was evil, a monster (V) ... no ... I was just born poor in a country where the Wealthy manipulate, use, abuse, and economically enslave 95 percent of the population. Rich Republicans, Rich Democrats ... same-same ... rich ... they take turns fleecing us ... our few dollars ... pyramiding the wealth for themselves."