The gruesome murder of pregnant Marine Maria Lauterbach was – and continues to be – a blockbuster story for The (Jacksonville, N.C.) Daily News. She was a soldier who was murdered, her bones later discovered in a fire pit. The story has taken many twists and turns. One of the most interesting, from an ethics standpoint, involves a reporter, a sheriff's deputy, and an intern in the District Attorney's Office.

As the criminal investigation of the Lauterbach murder unfolded, Daily News reporter Lindell Kay pulled ahead of his competition by developing a confidential source that fed him exclusive details about the crime and the lead suspect – another Marine by the name of Cesar Laurean.

Local authorities were naturally concerned about the leaks to the Daily News. The sheriff's department assigned an undercover deputy to identify and silence the confidential source.

The officer used a bold – and deceptive – method of police work. He called reporter Kay and posed as a journalist for Newsweek. He asked Kay to share his confidential source, ostensibly to ask the source some questions for a possible story. Kay received his source's permission and then turned the contact information over to the undercover deputy.

The cop tracked down the source – an intern at the local district attorney's office by the name of Robert Sharpe. Sharpe had access to reams of confidential information about the Lauterbach murder investigation, which he allegedly offered to sell to the undercover investigator. He was promptly arrested and charged with embezzlement and misdemeanor larceny.

Reporter Kay and his colleagues said they were outraged by the deputy's approach. "Our reporter feels really abused and disrespected," Daily News Executive Editor Elliot Potter reportedly told local news media and bloggers, adding that his paper didn't want to become a part of the story it was covering. The intern was also angry, but with the paper. He said he believed that the paper should have protected him.

To what extent, if any, was the Daily News righteously aggrieved? The police action clearly put the paper in an awkward position. The reporter had promised confidentiality and was deprived of his ability to keep the promise when he was tricked by the deputy into exposing his source. The paper could not carry out its responsibility to be trustworthy.

The paper can argue that the cops acted unethically, which we note is different than acting illegally. The deputy's actions were not unlawful. As legal scholar Jerome Skolnick has observed, "Police are permitted by the courts to engage in trickery and deception and are trained to do so by the police organization" at the investigative stage of a criminal prosecution. That means neither the paper, nor the rest of us, can depend on the court to protect us from deceptive police methods.

That said, there is another moral to this story. Taking on a confidential source has its downsides, including the possibility of inadvertent disclosure. Because the risk of that harm is always present, journalists should promise anonymity to a source only in compelling circumstances – that is, when it is the only practical way to bring crucial information to the attention of the public.

In this case, the journalist did not make the case that promising confidentiality to this particular source was in the public's best interest. The paper did not present evidence of a cover-up or lack of attention to the crime by law enforcement. The investigation was proceeding apace. In the absence of a compelling reason to use a confidential source – and incur the responsibility to maintain that pledge of secrecy – a reporter should stick with named sources or just wait for the story to unfold.

That way, the journalist won't risk arousing public curiosity about the wisdom of promising secrecy to an unscrupulous source. Sources do not have to be pure, but their motives and information should be credible. In this case, the source's motive was not. He was apparently willing to sell details of a murder investigation to a journalist with a checkbook.

That twist to the Lauterbach murder story is tough for a journalist to explain.