(CNN) — A suspicious letter addressed to President Barack Obama was intercepted Thursday, and is believed to be connected to two threatening letters sent this month to New York Mayor Michael Bloomberg and a group Bloomberg founded, a law enforcement official briefed on the investigation said. The official, who said the letter addressed to Obama was similar to the other two, did not disclose details, including whether there was a message. Preliminary tests on the letters sent to Bloomberg and his group indicated the presence of ricin, New York police have said. The law enforcement official did not say whether any substance was found in the letter addressed to Obama.
The suspicious letter addressed to President Barack Obama and intercepted Thursday was postmarked Shreveport, Louisiana, said a law enforcement official who had been briefed on the investigation. That's the same location where threatening letters sent to New York Mayor Michael Bloomberg and a group he founded were postmarked.