MISSOULA, Mont. -

The parking lot at Big Sky High School was notably empty Friday morning as some students stayed home on the day a bomb threat was targeted to occur.

School officials notified students and parents Thursday morning that graffiti discovered Monday morning in a school bathroom said the school would be bombed Friday, September 13th.

Missoula police have increased their presence at the school, and administrators said an ongoing investigation did not identify any immediate danger to students, but they told parents they had the option to keep their kids home from school Friday.

School officials said several sporting events could also be blamed for a drop in attendance Friday.

We've requested attendance numbers from the school district, and will update this article when they're received.