As part of an internal probe into safety lapses that recently caused a train tunnel to flood in Singapore, transport operator SMRT decided to employ a unique tactic: offer amnesty for employees who came forward and owned up to cutting corners in their work—ahead of an internal audit.

SMRT’s offering of an employee amnesty program is the latest example of an uncommon internal investigative tactic compliance departments sometimes use to get deep into the weeds of compliance lapses and help prevent future misconduct. As one chief compliance officer put it: “Amnesty programs are known to be a highly effective means of getting to the bottom of ethics and compliance issues in large organizations.”

Furthermore, the Department of Justice has said it views “innovative and effective” employee amnesty programs as part of “exceptional cooperation.” The gist of an employee amnesty program is that the employer promises not to fire or bring claims for damages against employees who come forward with information, but they are not shielded from criminal prosecution, and these programs typically are not extended to senior management.

Although rare, employee amnesty programs have been used with some degree of success. SMRT’s amnesty program, which ended Nov. 3, did result in employees coming forward with information. In a statement, SMRT said several submissions concerning scheduled maintenance works not being carried out were received from its building and facilities maintenance group.

Maybe an internal, non-public employee amnesty program is the best way to go, if any concerns linger that compliance controls and internal audit are not catching everything, especially from an ethics and corporate culture standpoint.

Over the last decade, a handful of other multinational companies—mainly in Germany—have used employee amnesty programs, also with some degree of success. Consider the following examples:

In 2007, Germany-based electronics and engineering giant Siemens offered a company-wide, three-month amnesty program to employees who came forward with information “relating to possible violations of anti-public-corruption laws … to expedite the independent investigation and facilitate clarification.” This program resulted in at least 66 employees coming forward.

In 2009, Germany-based commercial vehicle maker MAN Group launched a one-month amnesty program for employees who came forward with knowledge about potential bribery and suspected illegal commission payments.

In 2013, Germany-based ThyssenKrupp Steel offered a two-month employee amnesty program regarding a rail cartel case, resulting in more than 20 leads.

In 2013, Canada-based engineering and construction company SNC Lavalin launched a 90-day amnesty period for employees who came forward with information about potential corruption and anti-competition matters.

In 2015, Germany-based automaker Volkswagen extended amnesty to employees with knowledge about how the company cheated on U.S. emissions tests. About 50 employees—including several division heads—came forward with information.

What is not so clear is the extent to which U.S. companies, and those in other countries, offer employee amnesty programs, since the details of internal investigations are rarely publicly reported. This raises a key question for legal and compliance professionals: Is an employee amnesty program a strategic move or an act of desperation?

Should it be used only as a measure of last resort—after all compliance avenues have been exhausted and a thorough internal audit has been complete—or at the start of an internal investigation? For companies that have in place internal reporting channels, an amnesty program can be perceived as an implicit admission that those channels were ineffective—a red flag on its own, deserving of attention.

From a legal and compliance standpoint, moreover, wouldn’t it be better to play it safe and keep an employee amnesty program hush-hush? Employees with knowledge of misconduct must worry about more than just their job; the fear of facing criminal charges and financial and reputational ruin will weigh heavily on their mind, as well. Thus, even if employees are promised the security of their job, what is the benefit to the company of attracting unnecessary attention when there’s even the slightest possibility that no employees come forward at all?

Maybe an internal, non-public employee amnesty program is the best way to go, if any concerns linger that compliance controls and internal audit are not catching everything, especially from an ethics and corporate culture standpoint.