Astonishing revelations about politicians and significant public figures sell papers. To paraphrase a famous definition of news: someone, somewhere profits - and with a good story, the relevant newspaper is right up there with the profiteers. And where someone profits, someone suffers. Perhaps it's just the person whose corruption has been exposed, but it can be the journalist responsible for writing the story. Investigative journalists in Ireland admit to a certain amount of hostility, even verbal abuse, arising out of articles they've written, but few feel they are putting their lives at risk. In other parts of the world revealing corruption is certainly life-threatening - journalists in countries like Algeria, Colombia and most recently Zimbabwe (to name but a few) put their lives at risk, and die, every year.

As yet, we are not aware of politicians or high-profile businessmen hiring hit men to seek out Irish journalists. But the world of violent crime is a different issue; crime reporters in Ireland have admitted to receiving death threats. In June 1996, Veronica Guerin, an investigative journalist with the Sunday Independent who wrote several stories revealing amazing details about the world of crime and its main movers, was shot dead. In her book Veronica Guerin: The Life and Death of a Crime Reporter, Emily O'Reilly - now the editor of Magill magazine - raises questions about the role of the crime reporter and the issue of risk-taking.

O'Reilly quotes a story in the Sunday Independent where Guerin described her role as she saw it herself: "I am letting the public know exactly how this society operates." However, other journalists didn't agree with her way of carrying out this task: Vincent Browne, writing in the aftermath of Veronica Guerin's death, said investigating crime and criminals as Guerin had done was not the function of journalists; this was the role of the police, the courts and the prison system, he wrote. The job of the journalist was to look at the efficiency, or otherwise, of these State institutions. Having been threatened and shot at, Guerin knew her life was in jeopardy because of what she did. Under what circumstances might there be any justification for journalists to put their lives at risk?

According to O'Reilly, "Veronica was not revealing truths that would otherwise have been hidden . . . . Even if she saw herself as involved in a crusade against dangerous people, her journalism contributed nothing to their downfall." But perhaps the public has a right to know about more than institutions of the State - and details of criminals and their crimes, as aspects of "how this society operates", should be in the public domain. Guerin built up a network of sources in both the crime world and among gardai. She seemed to get some quite extraordinary information from both at times. But why? With reference to a particular murder Guerin revealed significant information about, O'Reilly wonders whether "perhaps the gardai had deliberately fed the information in order to provoke a reaction from a suspect or suspects". In other words, maybe gardai fed information to the press to facilitate their own work - not to facilitate the workings of a free press.

O'Reilly's book also addresses the controversial issue of the Sunday Independent's role: what is the responsibility of employers who encourage employees to continue working under hazardous conditions? Those hazardous conditions, in fact, added intrigue to Guerin's articles, says O'Reilly: "Had she not been in that danger, they would not have been such arresting stories." The articles did make great copy, and people bought the paper. What are the consequences of publishing contentious stories on the basis that they will boost sales?

Investigative journalism is often stranded in a complex maze of questions about the truth: what it is, why it's being told, who should inform the public, and when.

Exposing truth invariably hurts someone, and journalists often have to deal with the consequences. But should you draw the line at some point, and how do you decide?

next week

The Sunday Papers - What makes Sunday special for readers? What are the peculiar set of requirements that make for a proper Sunday newspaper?