From the LA Times: “The FBI is seeking four Chinese nationals in connection with an unspecified threat on the city of Boston, the FBI and the U.S. attorney’s office in Massachusetts said this afternoon.

Massachusetts Gov. Mitt Romney, in Washington for inaugural festivities, returned to the state after he heard the news.

Gail Marcinkiewicz, an FBI spokeswoman in Boston, said agents were “working aggressively” to investigate the threat, which came from an unknown and uncorroborated source.”

Thanks to ESWN for reproducing those photos.