Developing: Gun Reported at Pasadena High School Campus

Update, 5:15 P.M.: Police have swept three quarters of the school, which is actually named Blair International Baccalaureate, formerly Blair High School (LA Times)
Update, 4:27 P.M.: Three other schools in the Los Angeles area were on lockdown today.
Update, 3:17 P.M.: Police have been going through the campus systematically and methodically. So far, nothing has been found. Parents are complaining that warning phone calls starting coming in at 2 p.m., hours after the incident began. (via KNX1070)
Update, 1:27 P.M.: According to a spokeswoman for the high school, a student reported another student with a weapon (note, the word "gun" was not used) around 11:50 a.m. Police were immediately called and are searching all students. No weapon as been found. (via KNX1070)
Update, 1:05 P.M.: School is in lockdown, some students are still inside, and the report of a gun or gunman on the campus is unconfirmed according to a witness interview on KNX1070.
According to a Pasadena Star News brief posted at 12:39, "Pasadena police are searching the campus of Blair High School, 1201 S. Marengo Ave., to investigate a report of a person with a gun, according to KCAL9. Thus far, there has been no sign of anyone with a weapon." They say initial reports indicate one person has been detained.
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