We study the problem of secure decentralized event-triggered cooperative localization (SDECL) for a team of mobile robots in an adversarial environment, where the objective is to perform localization in the presence of a malicious attacker. We consider a scenario in which an intruder is able to attack the communication channels between exteroceptive sensors and filter of the robot and between two robots independently. First, we design a secure decentralized event-triggered cooperative localization in the multi-robot system against random Denial of Service (DoS) and False Data Injection (FDI) attacks. Then, we provide sufficient conditions that ensure the resilience and convergence of the proposed algorithm when the attacker signal rate is bounded. Simulation results show that by properly tuning the parameters of the event-triggered mechanism and considering bounded attack rate, the proposed algorithm is resilient against cyber attacks. Also, experimental results using four e-puck2 mobile robots have demonstrated the effectiveness of the proposed method.