I found this information while perusing the Internets. I added the last one, myself.
James Hatfield (Wikipedia) Mr. Hatfield was the author of Fortunate Son, an unauthorized biography of George W. Bush. The book detailed Bush's cocaine use and cover up of a cocaine arrest. He was found dead July 18, 2001, in a motel room, an apparent suicide.
Danny Casolaro (Wikipedia) He was working on a book that tied together the scandals surrounding the presidency of George H. W. Bush. He told his friends he was going to "bring back" the head of the Octopus. Instead, his body was found in a hotel in Martinsburg, West Virginia, on August 10, 1991, an apparent suicide.
Jake Horton (TIME) He was the senior vice-president of Gulf Power, a subsidiary of Southern Company, a cohort of Enron in the energy industry, and a major contributor to the Bush agenda. According to reporter Gregory Palast, Horton knew of the company's appalling accounting practices, and "... had no doubt about its illegal campaign contributions to Florida politicans - he'd made the payments himself. In April of 1989 Horton decided to come clean with state officials, and reserved the company jet to go confront company officials. Ten minutes after takeoff the jet exploded.
James D. Watkins His body was found on December 1, 2001 in the Pike National Forest in Colorado, a gunshot wound to the head. Mr. Watkins was a consultant for Arthur Andersen, the accounting firm for Enron. He disappeared on November 13 after he left work. He was described as a devoted family man who always called home if he were going to be late. Officials initially said that the death was suspicious, but have changed their tune and have ruled his death a suicide.
Charles Dana Rice (CNN) He was the senior vice president and treasurer of El Paso Corp., an energy corporation swept up in the recent energy scandal. Two months after the "suicide" of Enron executive Clifford Baxter, in the midst of questions about the accounting practices of El Paso Corp., Charles Rice was found dead of a gunshot wound to the head. His death was ruled a suicide.
J. Clifford Baxter (Wikipedia) Found dead in his car, shot in the head. Mr. Baxter was vice chairman of Enron Corp. when he resigned in May 2001. Enron has been hot copy lately with the revelation that they were the largest campaign contributors for George W. Bush. Was J. Clifford Baxter a potential witness to Bush foreknowledge of their wrongdoings? His death was ruled a suicide.
Katherine Smith She had been implicated in February in a phony documents scheme said to be related to the September 11 hijackers. One day before she was due in court, she was incinerated in her car after having hit a utility pole. An investigation revealed that the crash was minor and was not the cause of the fire that burned Smith beyond recognition. Who was really behind 9/11? Was Katherine Smith privy to that information? Why did she have to die, and who killed her?
John O'Neill He was Director of Counterterrorism at the New York offices of the F.B.I. until he resigned in August 2001. One of the world's top experts on Osama bin Laden and Al Qaeda, he grew to believe that "all the answers" regarding what they needed to destroy Al Qaeda lay in Saudi Arabia. However, starting in January 2001, Bush blocked all efforts by Mr. O'Neill to investigate Saudi ties to bin Laden. In the summer of 2001 O'Neill declared that the main obstacles to his investigation were U.S. oil interests. In late August, a frustrated O'Neill quit the FBI and took a position as head of security for the World Trade Center.
From Democrats.com: September 11: On O'Neill's second day of work on the 34th floor, the WTC is hit by the first plane. O'Neill makes it out of the building safely, calls his son to say he is OK,. then goes into the other tower to help guide those still inside to safety. Minutes later, O'Neill, along with hundreds of others, is dead, killed by the terrorist the Bush administration refused to allow him to pursue to the best of his ability.
Salem Bin Laden In 1979, Bush business Arbusto Energy obtained financing from James Bath, a close family friend. Bath had extensive ties to BCCI and the bin Laden family. Bath was the sole U.S. business representative for Salem bin Laden, the brother of Osama bin Laden. It is well known in certain circles that the Arbusto money came straight from Salem bin Laden, although Bush denies it. Salem bin Laden died when for no apparent reason, he flew his airplane into power lines where it became entangled, and fell 150 feet to the ground. "He was a very experienced pilot. He was a good pilot. We just can't understand why he decided to go right instead of left," recalled airstrip owner Earl May field.
Mel Carnahan In the midst of a heated race for the Senate against John Ashcroft, the Governor died in a plane crash on October 16, 2000. His death affected Democrats in two ways - it would hurt their chances of seizing control of the US Senate, and it would strongly impact the Presidential race between Al Gore and George W. Bush. Said St. Louis University political scientist Ken Warren, "There will be a sympathy vote, but that won't be enough to allow him to win. "I don't think the race will be very close. It's over." As we know now, Ashcroft lost to a dead man. Carnahan was elected by a landslide.
Dan Rocco He died on April 1, 2002, in a plane crash in Gainesville, Georgia. He was an executive vice president at ChoicePoint, the firm that gained infamy with their faulty "felons" list supplied to Katherine Harris during the 2000 election in Florida. As a result of this list, thousands of voters (mostly African-American voters) were wrongly identified as felons and purged from the rolls.
Karla Faye Tucker (Wikipedia) She was executed in spite of enormous protest from the public, even those religious groups that advocate the death penalty. Even Pat Robertson thought that Karla was truly repentant and asked George W. Bush to spare her life. He refused. Afterward, in a Talk Magazine interview, Bush mocked the woman whose death warrant he had sanctioned, pursing his lips and whimpering, "Please don't kill me!"
William J. Casey (Wikipedia) William Casey was CIA Director during the Reagan/Bush Administration. He died 2 days before he was to testify about his and others' involvement in the Iran/Contra scandal.
Donald Aronow (Wikipedia) He was a close friend of George H. W. Bush. According to the book "George Bush, the Unauthorized Biography," there is compelling evidence to conclude that Aronow was a drug smuggler and suspected drug-money launderer. He was murdered by professional killers on February 3, 1987. In the days before his death, he made many personal calls to George H. W. Bush.Tommy Teagle, a man interviewed by author Thomas Burdick, was afraid of being murdered by Bush because he had knowledge that Aronow and Jeb Bush had been partners in cocaine trafficking.
Amiram Nir He was a former Israeli agent who was in Jerusalem with George Bush during Iran Contra. He went under the assumed name of Pat Weber. Nir was scheduled to testify to the Senate subcommittee and it was feared he would reveal the truth. He perished when his aircraft was shot down with missiles from the helicopter of a man called Gene Tatum, 25-year CIA deep cover agent.
John Tower (Wikipedia) He was appointed by the Reagan/Bush Administration to chair the bipartisan committee to investigate the Iran/Contra scandals. He directed the Tower Report and had all the Iran Contra documents that told the real story. He was killed in an airplane crash later in Georgia in 1991. Also killed was his daughter, Marian.
Paul Wellstone was the only progressive in the U.S. Senate. Mother Jones magazine once described him as, "The first 1960s radical elected to the U.S. senate." He was also the last. Since defeating incumbent Republican Rudy Boschowitz 12 years ago in a grassroots upset, Wellstone emerged as the strongest, most persistent, most articulate and most vocal Senate opponent of the Bush administration.
In a senate that is one heartbeat away from Republican control, Wellstone was more than just another Democrat. He was often the lone voice standing firm against the status-quo policies of both the Democrats and the Republicans. As such, he earned the special ire of the Bush administration and the Republican Party, who made Wellstone's defeat that party's number one priority this year.
Various White House figures made numerous recent campaign stops in Minnesota to stump for the ailing campaign of Wellstone's Republican opponent, Norm Coleman. Despite being outspent and outgunned, however, polls show that Wellstone's popularity surged after he voted to oppose the Senate resolution authorizing George Bush to wage war in Iraq. He was pulling ahead of Coleman and moving toward a victory that would both be an embarrassment to the Bush administration and to Democratic Quislings such as Hillary Clinton who voted to support "the president."
Then he died.
Wellstone now joins the ranks of other American politicians who died in small plane crashes.
The powers that be will stop at nothing to get what they want. It's time we stopped them. Let's start with impeachment.