Authorities in Rotterdam and Lyon are investigating a possible connection between two violent attacks involving stones. In Rotterdam, a man suffered critical injuries after being struck while sleeping on the street. Meanwhile, a homeless man in Lyon was found dead, having also been attacked with a stone. Police suspect both incidents may involve the same assailant who fled to Brussels shortly after the Rotterdam attack. They are urging witnesses and international train passengers to remain vigilant and report any sightings of the suspect as the investigation unfolds.