BOULDER, Colo. -- A 16-year-old student was arrested in connection with a racial threat at Arapahoe Ridge High School in Boulder.

The threat was written on a lunchroom table Tuesday and The Boulder Valley School District had been working with the Boulder Sheriff's Office in an effort to identify the perpetrator.

The written threat said, "I'm killen all Mexicans! On Friday."

Wednesday morning, a male student at the school was identified and arrested for investigation of ethnic intimidation. The student's name was not released because he is a juvenile.

Investigators said they were able to identify the student because the Sheriff's Office School Resource Officer remembered which student was sitting at the table prior to the threat being reported. Faculty members also received a tip indicating the same student was responsible for the threat.

Another threat, written on a boys' bathroom wall at Boulder High School on Monday, is still under investigation. The scribbled note said, "KKK is back. All blacks will die Friday April 16."

Student leaders met Wednesday morning and decided to hold a unity week to show solidarity among the various minority groups at the school.