according to the Columbia Journalism Review, where some tabloid newspapers willingly pay for stories about scandals, and where some journalists now assume they should pay for gossip: "Once money enters the reporting equation, it has the potential to corrupt the whole journalist/source relationship," states the Review. Chequebook journalism became a national controversy in 1994 after it became public that the National Enquirer, a tabloid newspaper, had offered to pay $1 million for an interview with O. J. Simpson's friend Al Cowlings, before Simpson's murder trial. The paper also found the clerk who sold Simpson the knife allegedly used, and paid the clerk $17,000 for the information. Iain Calder, former European editor of the Enquirer, said that his paper pays well for tips about celebrities' private lives. During Simpson's trial, the judge admonished all attorneys to keep their witnesses away from the press to protect the "integrity" of their testimony. When the judge learned that Hard Copy and Star tabloids paid a future witness an estimated $100,000 to be interviewed, she eliminated the witness from the trial, potentially affecting the outcome of the case. The hounding of witnesses by the media led California Governor Pete Wilson to immediately sign a bill which henceforth made it illegal for witnesses and jurors in criminal trials to sell their stories until the case is finished. Howard Kurtz is among many journalists who states that paying for news stories, which he says was "essentially invented by the London tabloids," raises questions about their credibility. And writer Andrea Gerlin adds that the circulation wars among British newspapers has over the years led to rounds of "media witch-hunts, checkbook journalism, and intrusive stories about celebrities." In 2012, it was disclosed that reporters and editors at The Sun, a UK tabloid, had for years paid hundreds of thousands of dollars to police officers, along with a "network of corrupted officials" in the military and the government, to inform the paper about scandals. "They also cast a harsh spotlight on the freewheeling pay-for-information culture of the British media," noted the New York Times. Newspaper columnist Art Buchwald said that "the days of cheap news are over, and now all the players have agents." Consequently, newspapers which engage in chequebook journalism have to put up a lot more money than they used to. The witnesses in the Michael Jackson scandal were charging more to tell their story to the media