The News of the World's former investigations editor has been accused in court of hacking phones to break a story about cricket match-fixing.
Undercover reporter Mazher Mahmood strongly denied that the expose in the now-defunct Sunday tabloid involved the illegal interception of voicemail messages.
He told London's Southwark Crown Court he had received death threats since publishing the story alleging that a sports agent took bribes to arrange for Pakistan cricketers to bowl deliberate no-balls during the Lord's Test against England last summer.
Mr Mahmood said he launched an investigation after a secret source sent him copies of "incriminating" text messages from UK-based agent Mazhar Majeed's BlackBerry phone showing that match-fixing had been going on for a "long time".
But he insisted that the story "had nothing to do with phone hacking" and said he had no knowledge of the illegal practice during his 20 years at the News of the World.
The jury has heard that Mr Mahmood, posing as a rich Indian businessman, paid Majeed £150,000 in cash as part of an arrangement to rig cricket games in a gambling scam.
Prosecutors allege Majeed conspired with Pakistan's former Test captain Salman Butt, 27, and fast bowlers Mohammad Asif, 28, and Mohammad Amir, 19, to fix parts of the Lord's Test between August 26 and 29 last year. Butt and Asif, who are standing trial, deny conspiracy to cheat and conspiracy to accept corrupt payments.
Giving evidence from behind a screen to hide his identity, Mr Mahmood told the court that he began researching the story after a confidential source he had known for many years sent him information which was also passed to the International Cricket Council (ICC).
"They were incriminating text messages which showed these guys had been doing it for a long time," he said.
Alexander Milne QC, defending Asif, said the messages were downloaded from Majeed's BlackBerry and after asking the reporter: "Is this not hacked material?", Mr Mahmood replied: "No, it is not... One, you're assuming it's downloaded from the telephone without the knowledge of the person, and second this is nothing to do with hacking at all."