When the US Federal Bureau of Investigation announced on Monday that a man suspected of carrying out the arson attack on the Chinese consulate in San Francisco, California, had been arrested, those who want relations between the United States and China to go well must have sighed in relief.

According to Special Agent David Johnson, chief of the FBI's San Francisco office, a 39-year-old man, who has permanent resident status of the United States, was arrested on Friday after he turned himself in by calling police in Daly City, some 16 kilometers south of San Francisco.

Considering relations between China and the United States have been improving and go far beyond the bilateral scope, any delay in cracking the case could have cast a shadow on the good momentum that has been nurtured by the leaders of both countries and led to unhealthy international speculation on the trajectory of their interaction this year.