Taiwan’s top official said that many doubts still remain after a Chinese man was arrested near Taipei for crossing the Taiwan Strait on a speedboat. The official said it cannot be ruled out that these activities are “grey zone” attacks by China on Taiwan. The Chinese man was arrested on June 9 in the coastal neighbourhood of Tamsui after his boat entered a river that leads into Taipei. Taiwan has said that the man is a former Chinese navy captain who could have been “testing” the island’s defences. Meanwhile, China said that the Chinese man arrested near Taipei after crossing the Taiwan Strait on a speedboat was acting on his own.