German prosecutors are investigating an Eritrean man who pushed an 8-year-old boy and his mother into a train while the two were waiting at a railway platform in Frankfurt.

Federal Police President Dieter Romann said the Eritrean, whom he named only as “A”, had previously applied for asylum in Switzerland in 2006. Romann added that “A” had been known to hold a steady job and was considered “well-integrated”, but had recently caught the attention of Swiss police through a series of violent incidents.

Less than a week before killing the young boy and his mother, “A” had threatened one of his neighbours with a knife; an episode, Romann suggested, that may have been the reason why he had travelled to Germany, as he had subsequently been the subject of an arrest warrant in Switzerland.