TAIPEI (Taiwan News) — A 23-year-old university student has been detained for allegedly hacking Taiwan High Speed Rail (THSR) radio signals and triggering false emergency alerts that prompted trains to stop.

Taoyuan District Prosecutors’ Office said April 30 that the suspect, a Providence University student surnamed Lin (林), was brought in for questioning on April 28, per Liberty Times. He was released on NT$100,000 bail after interrogation the following evening.

The incident occurred on April 5, when three THSR trains were forced to make emergency stops. Station staff activated emergency procedures, instructing the trains to switch to manual braking, resulting in a delay of 48 minutes. THSR reported the case to police in the early hours of April 6, Newtalk reported.

Chief Prosecutor Chang Chun-hui (張春暉) deemed the case a serious threat and assigned Prosecutor Chung Han-i (鍾瀚逸) to lead the investigation. Authorities worked with the Railway Police Bureau and the Criminal Investigation Bureau’s Electronic Investigation Brigade to identify the suspect and filed a complaint on April 24, per Liberty Times.

Investigators made searches at three locations, including Lin’s residence and workplace. Radio equipment and multiple electronic devices were seized during the operation.

After questioning, prosecutors said Lin is suspected of exploiting vulnerabilities in a computer system to access a core network. He is also suspected of using electromagnetic interference equipment, possibly endangering public transportation safety and interfering with equipment, according to Newtalk.

The prosecutors’ office warned that any attempt to illegally disrupt public transportation constitutes a serious criminal offense.