Hong Kong police have arrested a fifth person accused of supporting overseas activists who allegedly endangered national security, in a further expansion of a government crackdown on pro-democracy dissidents. Police detained a 24-year-old man at the city’s airport on Thursday, a day after four other people were arrested for allegedly using companies, social media and mobile applications to receive funds for the overseas activists. “Investigation revealed that the arrested person was suspected of having connection with the group of persons arrested yesterday,” police said in a statement relating to the Thursday arrest. It did not identify the five suspects. Local…