This paper deals with the problem of distributed fault detection for a team of time-invariant multi-agent systems with switching topologies. Each single agent model is represented by a “virtual” model in the form of a continuous impulsive switched system. Distributed observers are designed with the LMI approach by using multiple Lyapunov functions, dwell time constraint and the H_-/H_∞ indexes. The proposed method detects the faults occurring on each agent (if any) and its neighbors (if any). Results of numerical simulations are provided to show the effectiveness of the approach.