A derogatory statement is considered loshon hara even when the information is common knowledge for, as stated above, to speak negatively of one’s fellow is shameful in itself.
Negative information about Jews appearing in newspapers may not be repeated. Newspapers often publish articles based on hearsay and thus, one is not even permitted to believe such information if the newspaper is its only source. Even after one has verified the information, he may nevertheless not repeat it.
Sefer Chofetz Chaim, 11 Tishrei, page 70