A 20-year-old man who threatened to carry out an attack on a high-speed German Inter City Express (ICE) in western Germany was remanded in custody on Friday.

An investigating judge issued an arrest warrant for the man in Aachen on Friday afternoon. He is to be remanded in custody, the Public Prosecutor’s Office announced.

The arrest warrant cites suspicion of attempted murder, grievous bodily harm and violations of the Explosives Act, among other things.

On Thursday evening, the assailant threatened to carry out an attack on a crowded ICE train en route from Cologne to Frankfurt and detonated two explosive devices.

At least 12 people sustained minor injuries in the incident on Thursday, shortly before the long Easter weekend. According to the Public Prosecutor’s Office in Dusseldorf, the motive remained unclear the following day. Investigators are considering various possible motives as they assess the incident.

A spokeswoman for the Public Prosecutor’s Office said there is evidence that the man can be “classified as belonging to the far-right spectrum.”

On the other hand, there are also indications that the man suffers from a mental illness, she said. The exact sequence of events has yet to be established.

Federal police officers detained the assailant at Siegburg station that evening. He is alleged to have first thrown the lit objects on the ICE train then retreated to the train toilet.

Other passengers detained him there until the emergency services arrived. The train was evacuated.

A police statement said that one person had presumably suffered a blast injury.

A spokeswoman for the federal police also spoke during the night of "minor, superficial skin injuries" among those affected. However, most of the approximately 180 passengers escaped with nothing more than a fright.