Supreme Court: Unlawful Use of Private Investigators Against Employees on Sick Leave in the Absence of Specific Suspicions

In its order no. 23578/2025, the Italian Supreme Court reaffirmed the limits within which an employer may engage private investigators to monitor employees suspected of misconduct.

 

Specifically, the Court clarified that:

• defensive controls are admissible only where based on specific and substantiated suspicions of unlawful conduct;

• investigative activity must comply with the principles of proportionality and data minimisation, avoiding continuous and generalised surveillance;

• in the absence of such requirements, the findings of investigations are inadmissible and cannot justify a dismissal for misconduct.

The case concerned a manager dismissed while on sick leave following an investigation that lasted 16 consecutive days, including holidays, and entailed surveillance not only of the employee but also of family members and acquaintances.

 

The Court of Appeal had already deemed such control disproportionate and unjustified, noting that the legal system provides alternative and less intrusive tools – such as the INPS medical examination – sufficient to verify any failure to comply with mandatory availability hours. The Supreme Court confirmed this reasoning, holding that the lower court’s assessment regarding the excessive intrusiveness of the monitoring was not subject to review in cassation.

 

The principle established is clear: while an employer may resort to defensive investigations, such measures cannot amount to systematic and intrusive monitoring of the employee’s private life. In such cases, not only does the collected evidence lose its probative value, but any dismissal based on it is unlawful.

 

The practical lesson for employers is evident: the legitimacy of disciplinary action cannot disregard compliance with the principles of proportionality, necessity, and protection of privacy. Otherwise, there is a significant risk of undermining measures that may be substantively justified but vitiated by the use of investigative tools inconsistent with legal safeguards.