Mazher Mahmood, the undercover reporter also known as the "Fake Sheikh", has been found guilty of tampering with evidence during the drugs trial of singer Tulisa Contostavlos. The Sun on Sun reporter was found guilty of conspiring to pervert the course of justice driver along with his driver Alan Smith, 67.
The pair were found guilty of plotting to suppress evidence in relation to the 2014 trial of the former N-Dubz star and X-Factor judge who was accused of brokering a cocaine deal in a story published by the Sun On Sunday in June 2013.
The case eventually collapsed over concerns Mahmood, 53, known as the "King of Sting", lied under oath and got Smith to change his account in order to secure a conviction against the star.
Contostavlos was allegedly filmed by the paper brokering an £800 ($1,018) drug deal by one of her friends for Mahmood, posing as a wealthy Bollywood film producer who was discussing acting role for her alongside Leonardo DiCaprio.
Following the set-up meeting at the Metropolitan Hotel in London in May 2013, Smith drove the former X-Factor judge home to Hertfordshire, during which time she allegedly spoke about a family member's problems with drugs.
During police questioning, Smith told officers about the conversation in the car. However, a day later after speaking to Mahmood and emailing his draft statement, Contostavlos's comments where she spoke of her disapproval for hard drugs were removed, the court heard.
Mahmood originally denied discussing the drugs conversation with Smith, but appeared to concede he had talked to Smith about what Contostavlos said about drugs in the car when questioned about it during the trial in 2014.
The court heard how Mahmood had a "vested interest" in prosecuting Contostavlos, as he wanted to exposing the pop star life of "smoking weed" and "arranging cocaine for mates" at a time she was being portrayed as a role model in the media.
Defence lawyer John Kelsey-Fry QC told the jury: "Mr Mahmood is not a policeman. He is a journalist. Whilst the prosecution may say he boasts of the number of convictions resulting from his work, securing convictions is not actually his job."
After the case again her collapsed in 2014, Contostavlos said outside the court she had been the victim of a "horrific and disgusting entrapment".
Both Smith and Mahmood will be sentenced on 21 October.
Simon Ringrose, Specialist Prosecutor in CPS Special Crime Division, said: "Mr Mahmood portrayed himself as the master of subterfuge and as the 'King of the Sting', but on this occasion it is he and Mr Smith who have been exposed.
"Mahmood and Smith tampered with a statement and then attempted to cover their tracks through lies and the destruction of evidence. By piecing together the various strands in this matter, the CPS was able to present a compelling case to the jury."
Ben Rose,Contostavlos's defence lawyer, said: "The real scandal in this case is that Mahmood was allowed to operate as a wholly unregulated police force, 'investigating' crimes without the safeguards which apply to the police.
"It was obvious from the outset that Tulisa should never have had to go to court. If Mahmood's evidence had been properly stress-tested instead of accepted wholesale by the CPS, we are confident it would have come to the same conclusion.
"Investigative journalists do important work, but Mahmood clearly went too far."