PORTLAND -- Racism has reared its head at a local religious school.

Last week, officials at a Beaverton Catholic school found racist remarks written on a poster featuring Democratic presidential candidate Barack Obama.

Jesuit High School’s president and principal co-signed a letter to parents detailing the event.

Officials say “a partial racial epithet” was discovered Tuesday, handwritten on a poster featuring both Obama and Republican John McCain on a wall near the school’s library.

 Background: Read the letter

The letter to parents goes on to say three teenagers who didn’t attend Jesuit High came on campus the day before the poster was defaced and asked “where to find Obama posters.”

One Jesuit High student described the three teenagers as acting with "threatening, aggressive behavior."

Officials alerted Beaverton police and an officer investigated. The teenagers have been identified as non-Jesuit, according to the school.

The school made an announcement to the entire student body, “informing students of the seriousness of the act and asking anyone with information about the defacement to inform the administration,” according to the letter.

The poster defacement was not the only racially-motivated incident at Jesuit High in recent days.

School officials also announced that a student was targeted with a note, left on a locker, with incendiary racial remarks on Thursday.

The same student on Sunday found a racist note off-campus, on the doorstep of his or her family home.

School officials are not identifying any of the students involved in the defacement or the target of the racist note.

Police are investigating both incidences. Neither school officials nor the police department will say whether they are related.

 Background: Students confess in Obama effigy incident

Just two weeks ago, a cardboard cutout of Obama was hung from a tree at George Fox University, a private Christian college in Newberg.

 More: Teen hopes to nab Obama sign thief

KGW Reporter Erica Heartquist contributed to this report.